Any psychologist here that knows about daddy issues?

I’m just trying understand my brother and his relationships. He jumps from one relationship to another. Our parents separated when he was two and I was 3. Him and our stepdad has always had a rocky relationship since we were young and got worse throughout the years. Him and I are very close to our mom however. We have a relationship with our real dad but not a close one. He just never really cared about us. He never disciplined us in any way and just let us do anything we want. There is no parenting at all except give us food when we come to visit. He is a heavy user of meth and him and my bro had an argument over it. Last year, he was finally diagnosed with schizophrenia and things started to make sense.

Anyways, my brother tends to jump from relationship to relationship and always in toxic ones. He actually dated a nice girl for a year but left her to pursue another girl. Him and that girl are now together and I see that’s it’s becoming toxic again. Could this be a case of daddy issues? I don’t have any problems in my relationship but I am concern about my brother. Why is does he tend to pursue toxic relationships?