Is your child ethnically Chinese or East Asian? Then maybe. Otherwise, I would not want my child to stick out like that unless I was with him. Sticking out like that puts him at more risk, just generally. If you are his parents, you are constantly watching for his best interests. Do you trust another family to do that?

Update Op?
Any more details?

I would say yes until I saw the price tag. You should only pay for the air ticket.

its not the where or with who as long as you know them well, it's the month long vacation away from family I would object

I'd be okay with a trip, but not a whole month. That's just a long time. It sounds like the trip has some natural breaking points, so he could go for part of the time and fly home when the other family flies to the next destination.

Yes, if I knew the family well and agreed with their parenting style. My daughters are adopted from China and this would be an amazing opportunity for them to visit their homeland. If they wanted to do it, absolutely, yes!