I live in China! What city will he be in? That will make a big difference. If he's in Beijing or Shanghai he should be able to find something. If he's in a 2nd tier city (Xian or Chengdu or Qingdao or someplace)
In Beijing gymnastics is offered through Multisport and one other group, I think they're called Sports Beijing maybe? They cater to expats and have a "Western" approach. They do do team gymnastics, but I think they are fairly limited as far as competitions and such go. The practices are held, as far as I know, in the gymnasium of one of the international schools. So we're not talking state of the art, but better than nothing. If the child doesn't speak any Chinese this would probably be his best bet. I think a Chinese gym with a Chinese coach would be a big culture shock. I know they have a girls team, not sure about boys.
Then there are local gyms. Almost any gymnasium here will have gymnastics classes but competitive Chinese gymnasts are usually chosen quite young and the training is extremely intense from an early age. They're not necessarily plucked from kindergarten like everyone thinks, lots of them have parents who bring them to these gyms and insist on training (Chinese parents are extremely competitive), but lots of the gyms will only seriously train kids with the "right" body type, no tall parents, etc. There are local competitions and "clubs" but most of the gyms in China are not private and they aren't solely for gymnastics, they're these big sports complexes. Recreational classes are fine through these though. In Beijing the most well known gym/sports complex is Shichahai, which is where a lot of Olympians have trained. They do recreational sports of all sorts. I have my son in a recreational class at another local gym and it is fine so far (but my son is half Chinese -- my husband is from here -- and speaks the language), but I don't think I'll even try anything competitive until we're back in the States.