Lao Mao: Should I do this favor?

My cousin left US back to China and opened his business. But he changed his and his wife's address to mine, including bank statement, credit card address.. Should it incur any legal problem? A few days ago, he asked me whether I can host his kid to enter school. Their kis was born in US but was brought up in China. According to my knowledge, to attend public school, the parents should present last three months' gas or electronic bill and the bank statement. So my cousin asked us if we mind adding his name under our gas bill. Is there any legal problem? Can I anyway host his kid, since he and his wife did not pay the tax right here? To be honest, my cousin and his wife helped me a lot when I moved to this city. I would do them my best favor, if possible. Btw, my cousin and his wife are holding Chinese citizenship.

Lao Mao, could you give me some legal advice? Thanks ahead!