DEAR ABBY: "Torn in Texas" wrote that her widowed father-in-law visits them every weekend, leaving no time for her family to have a weekend just for themselves. May I suggest that "Torn" contact the Office on Aging nearest to "Pop" and find out what programs are available for seniors. If he has the capacity to drive an hour each way to their house, perhaps he could volunteer.
It appears that Pop has a lot of life left in him, and it's a shame that he spends so much of it alone. If he could become involved in some activities during the week, they might overflow into his weekends, keep him busy and productive, and alleviate his family's guilt. If you only reduce the number of times he visits each month, he will be alone that much more and probably won't admit that he is lonely.