Some people said the brother just wanted the special atmosphere OP created for her baby shower without putting in any work himself. Many pointed out that most women don’t want a proposal in front of an entire family anyway, and hijacking someone else’s event is tacky and cheap.
Others agreed that his attempt ruined the moment and that he deserved the bill OP sent afterward. Commenters also noted that the mom was completely wrong in thinking it was “lovely” or “two birds, one stone.” Family drama is messy, but sometimes saying no is the only way to protect your own milestone.