Sorry for the clunky title didn't know what else to write!
Long story short, been with DH for 7.5 years. He's got a 12yo DD, he has 50/50 custody of her although sometimes more if her mum goes away with her partner like atm. She has an older brother he's 19, DH isn't his dad, was sort of a stepdad figure when he was with his ex but since they split they didn't have contact and his ex made it clear he wasn't his dad so she wasn't going to allow it.
Anyway, yesterday her mum and younger siblings (toddlers so under school age before anyone asks) and mums partner went away leaving DSD with us and her brother on his own. DSD went back today because she'd forgotten something and then called DH in a panic.
He went round there and her brother was on the sofa sort of out of it and he'd clearly been beaten up, he had injuries on his face etc. DH managed to sort him out and he brought him back here with DSD, apparently DSD was anxious about him being on his own.
When I got back from being out with my sister he had gone back to sleep on our sofa. Hearing from DSD their mum had kicked him out so he obviously snook back when he knew they'd be away. The brother said he didn't know who beat him up but didn't want to report it, said he’d sort it which does sound as though he knows who it is. DH thinks he should stay as he doesn't want him getting into any trouble or hurt again, he doesn't think he's got a concussion but another injury to the face/head so soon obviously wouldn't be good.
I personally don't feel comfortable with a random boy here but he says he's his daughters brother. Am I being U or is DH being soft (for context, he is a head of year in a school and is quite soft on troubled teens especially as he thinks they need kindness not just discipline)