Re: Calico critters
I think that's a lovely gift for your son.
My dd has a Calico Critters dollhouse that she got from her grandma. She's 6 and a half and has been playing with it for about 4 years! The pieces hold up very well, although some of the tiny stuff (food, etc.) gets lost easily. After 4 years, some of the fur has rubbed off the critters as well, but I think that's to be expected. Dd loves how detailed and realistic the pieces are.
The big downside, to me, is that Calico Critters stuff is REALLY expensive. You get much less per set than, say, a Playmobil set at the same price.