He has good days and bad days, days when he cannot remember much of anything - even those magical Stanley Cup seasons when his shrewd trades earned him the nickname "Keith the Thief" - and days when glimpses of the past come into focus.
Still fit after all these years, Allen has a handshake stronger than those of most people half his age as he greets his holiday well-wishers.
"Look at that grip!" former Flyers defenseman Joe Watson said during a visit last week. "He's trying to break my hand."
"No I'm not!" Allen shot back, smiling sheepishly.
Watson, an original Flyer in 1967 and a member of the Broad Street Bullies when they won their Cups, let out a belly laugh and affectionately wrapped both of his hands around Allen's. It wasn't so much what Allen said that brought joy to Watson as the ability of his former boss to comprehend the remarks.
Allen then asked Watson to "get me some Saskatoons," referring to fruit berries that are especially popular in western Canada, where both men grew up.
Again, Watson shook with laughter.
Allen, a defenseman who played briefly with the Detroit Red Wings and was on their 1953-54 Stanley Cup championship team, smiled when Watson's wife, Jamie, introduced herself. He gently lifted her hand and kissed it. Three times.
"He's a flirt," said Joyce Allen, Keith's wife of 65 years.
This was a rare sequence, one in which the beloved Allen briefly interacted with his visitors. He usually sleeps most of the day, his wife said, and he stays in a part of the facility designed for memory-loss patients. His wife lives in a cozy apartment at the complex, and her living room includes photos of the couple throughout the years, along with some of her husband in a Red Wings uniform and his days with the Flyers.
A few minutes after he visited with his guests, Allen became emotional and began crying.
Watson comforted him.
Confused, Allen raced back in his mind to his playing days. He told Watson, "I just fought a 300-pound guy, and he did me in."
Godfather of the Flyers
Allen lives in what Sunrise calls its "reminiscence" unit, which has both dementia and Alzheimer's patients, and his wife joins him for some meals and other visits. His week includes activities such as arts and crafts, bingo, movie-watching, and exercise classes. He lifts light hand weights in the exercise class, one that has three men and about 20 women.
"He's a ladies man," said Lania Adderly, a care manager at Sunrise. "He likes being around the ladies."
"The girls all fuss over him, which he loves," Joyce Allen added.
Adderly reads the newspaper with Allen every day. She said that he still reads and is aware of current events, and that he knows the NHL is in a work stoppage.
"I asked him about hockey, and he said, 'It's not here anymore,' " Adderly said.
She said Allen's favorite activity is karaoke.
"He loves singing Frank Sinatra songs," she said. "One of his favorites is 'Yes Sir, That's My Baby.' "
There are several memory stations in the "reminiscence" unit, and they include mental exercises to keep the patients' minds sharp. In one station, patients may be asked to touch and identify objects or attempt to knot a tie.
"He still knows his birthday [he will be 90 on Aug. 21], and knows he's from Canada," Adderly said. "He talks about it sometimes. He still remembers lots of stuff."
Keith and Joyce Allen have three children, Brad, Traci, and Blake, and four grandchildren. They moved into Sunrise in October after their home in Beach Haven Park, N.J., was destroyed by Hurricane Sandy. Since moving there, they have been visited by a growing number of former Flyers and their wives, along with Ed Snider, the team's founder.
"His spirits are up a bit, but he's going through a tough time, and it's tough on Joyce," Snider said from his home in California last week.
In a way, Allen is the godfather of the Flyers. He was there for their birth as their coach, and as the general manager he was the architect behind their stunningly quick rise to NHL kings in just their seventh season.
"Keith and I were awfully close in building the two Stanley Cup winners," said Snider, chairman of the Flyers' parent company, Comcast-Spectacor. "I was a lot more active on a day-to-day basis back then, and we worked very well together. I don't think he ever made a bad deal. Basically, even though he's in the Hall of Fame, I think he's underappreciated for what he did."
Perhaps, but Flyers fans still remember. When the team posted a photo of Allen and former Flyers Watson and Bill Barber on its website recently, it received an overwhelming response from fans on social media, said Zack Hill, the team's publicist.
Joyce Allen was genuinely touched to hear that.
"Are you trying to make me cry?" she asked in a pleasant tone. "We think of the fans a lot."
'Feel for talent'
Joyce Allen passes some of her time by going on shopping trips with Donna Ashbee, the widow of Flyers defenseman Barry Ashbee. Allen said that her husband began having some memory problems about three years ago and that the lapses have increased over time.
"It's gotten worse in the last six months," Snider said. "A year ago, I was talking to him about the team. He wasn't 100 percent sharp, but he was able to communicate with me."
During his prime, Snider said, Allen "could evaluate players better than anybody. He would say that a certain guy would turn out like this, and he was always right. He had such a good feel for talent, and he could deal with any [general manager]. So likable. Not boisterous, but low-key and just a nice human being. Everyone trusted him."
That included the players. After the 1977-78 season, Watson, who was about to turn 35, had his end-of-year meeting with Allen and coach Fred Shero. They told Watson they planned to go with younger players, but if he was agreeable to playing 35 or 40 games the next season, he was welcome to stay.
If not, they would trade him.
Watson, wanting to remain a full-time player, opted to be dealt.
"They asked me where I'd like to go," Watson recalled. "I said, 'Well, I wouldn't mind going to Colorado. It's nice there, and I like to ski.' "
Watson laughed at the conversation.
"I got traded to Colorado, and I was there 16 games and broke my leg very badly and had to retire," he said.
Watson was injured in a 1978 game against St. Louis when he was checked into the boards and his thighbone was shattered.
"I'd tell Keith, 'You sent me out there to have fun, and I didn't have a lot of fun. I broke my leg, and I almost killed myself!' We used to laugh about it."
But Watson appreciated Allen's compassion as a GM.
"He moved Joe where he wanted to go," Snider said. "He always tried to take care of our guys."
Two of Allen's boldest decisions were hiring Shero, then a longtime minor-league coach in the New York Rangers system, and using primarily the draft to remake the Flyers into a physical team, one that became known as the Broad Street Bullies. Both decisions were made after discussions with Snider.
The Bullies won titles, packed arenas, and became hated by fans around the league - and by Clarence Campbell, the league's president.
In the middle of the night, it wasn't unusual for Campbell to call Allen to chastise him and fine the team for an out-of-control brawl.
Joyce Allen recalled her husband responding with a profanity. "But then in later years, they became quite friendly."
Just like almost everyone who has come into contact with the classy Allen.
Contact Sam Carchidi at email@example.com. Follow on Twitter @BroadStBull.