Foster wet the bed and he’s really embarrassed

Our 13 year old foster son has only been in our care for a few months. My wife says he came to her this morning very upset and in tears and told her he “wet the bed.”

He said he was sorry and he promised to never do it again and he didn’t mean to and please don’t get mad at him and all that. He seemed really embarrassed.

She told him it was okay of course and not to worry. But when she went to change the sheets she didn’t notice anything wet though so she asked him if he was sure. And he pointed to a little tiny spot.

Let’s just say it wasn’t urine and it was the other male fluid. My wife is wanting me to talk to him because she says he seemed really confused and not understanding what happened and she doesn’t know how much education he’s had in the other places he’s been.

I agree I should talk to him but it’s a little awkward because I haven’t known him that long. Is it even appropriate for me to have these conversations with him? How explicit do I need to get?

I’ve read getting him a book might be a good idea and I might do that but I still feel I need to have a conversation with him like tonight so he doesn’t worry too much.