The thing with gifts is to thank them for their intent, even if you tell them why you’re not going to keep the item.
If you don’t succeed in returning it, you might also consider giving it to someone with a movement disability, for whom the assistance might outweigh the privacy issue.
I don’t recommend OP take on a toddler until they master their own emotions.
Good for you, though! Sending you a hex against other random stress-inducing disasters befalling your family while you’re navigating this difficult passage.