Not sure how fat he is currently, but as you get older staying lean should be the main objective, bulk doesn't age well, not to mention just healthier to be lighter as you age just for everyday functional purposes.
To be honest , my wife's dad recently had a few "touch and go" days.
Working seemed a tad pointless for a bit, but wtf, I'm human.
He took a rapid turn to full recovery and my wife and I were thrilled.
That was quite an early Christmas present to say the least.
Funny how you mentioned it because I'm losing wt now.
In fact, I went out today and stocked up on organic fruit, meats , veggies, etc.
I've got a full slate of wt workouts with cardio planned for the Christmas/ New Years weeks.