That is a odd response to just take it and leave, did he or mom say "thank you"? How old is their child? Maybe he thought it wasn't age appropriate? Do they celebrate Christmas?

I don't think giving gifts is weird at all. I always give my dck's gifts and the parents so far have always loved it and thought it was thoughtful and they appreciate that I also buy for their siblings if they have any.

I wouldn't worry too much about it. As long as the child enjoys the gift that is all that matters