How do most handle this?

Really random question and not a big deal just curious how other parents deal with this type of thing. My 2.5 year old and I go to a drop in playgroup every Monday, basically just a gymnasium full of toys, all the parents sit on benches and the kids just play. There’s a kid there about 3.5/4 years old, he is constantly taking the toys my son plays with, my son picks up a blue truck, this kid runs over and takes it, he does it to other kids too. I see it happen, I see my son getting upset (he’s not the type to hit or get aggressive he’ll just cry) try to take it back and then he eventually runs over to me upset. I tell him I saw what happened and I’m sorry that truck got taken when he was playing with it but these things happen, let’s go find another truck. I’d really like to tell the kid to just give my son the damn truck back and stop taking shit and share but...not my place 😂 and I know sharing is SO hard at this age, clearly my son has an issue with it too. But I’m also watching and I see what’s happening, his mom is on her

Phone or talking to other moms, if I saw my son take a toy from a kid I’d make him give it back. What do you guys do?