Today 10 year old son made me chose between believing him or his friend about the theft of $100

Really killing me on what to do here... but the short story is, my 10 year old son had a school buddy over today to play. They went to go to the convenience store, and after they came back, my son was acting funny. He was playing by himself in the yard while his friend was up in his room playing on his phone.Son told me a long rambling story about how he found $100 bill on the playground, and his friend told him to take it to 7-11 so they could split it. He says his friend told him not to tell me, and basically 7-11 would not change a $100 bill so they ended up getting a Visa card (?).No question this was my $100 bill that was sitting on my kitchen window sill while they were playing in the kitchen making slime earlier today.But son insists he found it on the playground, to the point of being violently upset and crying.My son also has mild autism, which manifests itself socially, where he has awkward social interactions and will exaggerate stories, etc to impress his peers and build himself up. He is otherwise quite popular with his peers, is athletic and does team sports and the class clown. But he does have issues with not feeling adequate to his peers, and feels like he has to compensate with jokes and exaggerations, etc.So I am resolved that I will not really know the answer to what happened here. Did his friend take the $100 and it fell out of his pocket on the playground/he dropped it out of guilt, etc? Or did my son take it to impress his friend with a cool experience, thinking maybe he would put it back later, etc.Bottom line is, I'm at a loss how to deal with him about this.Where I have left it was to tell him that it doesn't matter to me if he took the money or his friend took the money... he knows the truth, and no matter what the truth is, this is an important lesson to learn about growing up.. that it's not a good idea to try to impress your friends.. or that sometimes his friends may try to pressure him into doing things... or that sometimes maybe friends will trick him and not everyone is a "good" person.That if he did take it, he knows he took it, and this is a good lesson for him to know that it's not right to do bad things to impress his friends.I honestly don't know what happened. But I don't want to come down hard on him without knowing the absolute truth. And also, even if he did take it, knowing he was trying to "fit in" or impress his friends and things got out of hand.Not sure what my question was, but maybe if anyone else has experience in this kind of situation I could learn a different/better way to have dealt with the situation. via /r/Parenting https://ift.tt/2HilbaV