The older the fiddle the sweeter the tune as the saying goes!
There are lots of girls in their late 20's early 30's who actually prefer the older guy and 41 is by no means old. It depends on attitude also. You could meet a 30 something guy/girl that comes across as old beyond their years due to their attitude and vice versa.
Your uncle might just need a bit of a confidence boost. If you consider mentioning the escort route to him, there's lots of ways of doing that without drawing suspicion upon yourself......i.e. overheard lads chatting about...blah, blah.....saw an article in newspaper about...etc. etc. Just drop it into conversation casually if you have a close relationship with him and you think he could handle the subject.
Good luck with it all and hope your uncle starts to enjoy living life with whatever he decides.