Is This Normal

So I'm not actually a parent. But I have custody of my 16 year old brother. He got raped at a party by a guy and our "mother" had been harassing us. She's been making her, my boyfriend, and my brothers life hell! About a week and a half ago he wet his bed. We thought nothing of it. But it kept happening so my boyfriend brought him some pull ups and told him if he ever needed help with wet sheets just tell him. He also started therapy over the phone. Is it normal to wet the bed after trauma. I really wasn't sure because of it's something physical we plan on taking him to the hospital. But could it be trauma?