Has watching 'Monk' helped your relative?
Only in the sense that it helps to know that there are enough others like him that they can make a show about one of them and people understand what it's about and think it's somewhat charming. He was telling me about a scene where Monk spotted two adjacent pots of coffee, regular and and decaf, and then poured one into the other in order to get the levels even. He doesn't do anything like that (although he used to flick light switches on and off in multiples of 5) so he was able to laugh about it.
As far as Monk's fear of germs, obsessive cleanliness, not wanting other people to touch his stuff, etc., that's about the same as Monk, and just seeing the humorous aspects of it doesn't seem to improve the situation. Just watching Monk is not going to take away his dislike of touching or even being around any animals.
My relative thought it was funny that Monk made an entire trip to Mexico without once eating, drinking, or going to the bathroom. But it's entirely believable that if he had to go to Mexico he would do the same.
In the area of food and eating my relative is undoubtedly more obsessive than Monk. This is a painful subject for him as it limits his life in many ways. He doesn't really appreciate humor about his personal situation in this area. But perhaps if the humor was directed towards a fictional character it would seem funny to him.