The best thing my mother did was separate from my dad who was emotionally abusive. If he stuck around, I'm not sure what shape I would have been once I reached an adult. As a matter of fact, he stuck around too long.
It took me years to come to terms with what he subjected us to, and understanding that there were other excellent male role models who I looked up to - Grandfather was one, and some extended family who pitched in. We all think there's this perfect family model that exists, where dysfunction could never spring up, but quality parenting can be found in even the most unlikely of circumstances and scenarios. In a single parent situation, coming to terms with raising a child on your own and the reasons for it is difficult to overcome, so there's added pressure there. How a parent deals with that pressure shapes how they raise the child. It ain't easy but I've seen far too much fukkeries in all sorts of families to discredit the efforts of single parents ( and I'm including single dads in here)