Mack's nightmare began with a slight weakness in his left hand. Because he was lefthanded and a barber at Action Hair Studio, he assumed it was due to overwork. Then it spread to his entire arm.
He tried physical therapy and cortisone shots, but nothing helped. In 2006, doctors diagnosed him with ALS. Although doctors can slow progression of the disease, there is no cure.
Things took a turn for the worse when Mack fell while trying to take his daughter out of her car seat. Since he couldn't use his arms, he laid in the street until neighbors noticed and helped him. He kept pushing on but was falling more frequently.
By 2008, he had no use of his hands or arms. The only way he could walk was if two people were available to balance him. Although his voice was low, he still was able to speak. But by 2009, he was lying in bed all day except for visits to the bathroom.
The following year, he couldn't walk at all. Nurses and aides cared for him around the clock. Since eating was a problem, he was on a soft-food diet. Talking became even more difficult. He got a tracheotomy after a 2011 incident that left him unconscious and not breathing and moved into Garden Spring Center. He was supposed to be there for only two weeks. It's now been more than three years.
Mack is on a ventilator and has no motor function from the neck down. He's in pain all day every day. He can't eat, smell or speak. But he feels blessed to have a beautiful wife and daughter.
"Your body is your prison," Williams said during a recent sit-down in his office. "That's why I'm just amazed at the spirit of my cousin, who remains as positive a person as you've ever met."
Williams kicked off the challenge Monday with an official weigh-in overseen by his personal trainer. At 5 feet 11 inches tall, Williams has a 38-inch waist and admits to working out only sporadically. He's now on an intense training program that includes weight training, jogging and spin classes. He plans to cut the carbs and eat lots of fruits and vegetables to shed 15 to 20 pounds. If enough Philadelphians join in his challenge, he could raise a nice chunk of change.
"All of the proceeds will go to the ALS Philadelphia chapter and the facility where my cousin Wayne is staying," Williams told me. "I thought that doing this will help bring attention."
It could catch on.
We've seen stranger things become popular. Who would have thought that the phenomenon of people videotaping themselves dumping buckets of icy water over their heads would have turned into such a social-media sensation?
On Friday, the ALS Association announced that a jaw-dropping $100 million had been raised in a one-month period thanks to the challenge. The previous year (from July 29 to Aug. 29), ALS raised a paltry $2.8 million.
Just a couple of days in, Williams already has a $500 pledge from a local attorney payable if he drops 20 pounds. Those interested in pledging should email him at Seth.email@example.com. We'll check in with him in early December to see how he did and publish the results.
"Maybe it's a little silly for a D.A. to try to get money from people by trying to lose weight," said Jeff Shuck, CEO of Plenty Consulting, which helps nonprofits with peer-to-peer fundraising. "But why the heck not?
"I like the D.A.'s idea a lot," he said.
So, what do you think, Philadelphia? Are we with him on this?
On Twitter: @JeniceArmstrong