When Kourtney found out she was pregnant with Mason and was unsure about what to do, it was Scott who was insistent that she go through with the pregnancy. She probably would have anyway but he at least paid lip service that he wanted to and was ready to be a father. I don't have any sympathy for him about the kids thing. If he didn't want any more after Mason, or after Penelope, he didn't have to.
I do have sympathy for his obvious drug and alcohol issues, and for losing his parents. But he has the means and the opportunity to go to rehab or at least get therapy and he just won't.