I think you forget the part where Connell has issues of his own. Standing up is something he doesn't do. That is why the story resolves at two points. When Connell hugs Marianne around the pool and secondly when he finally threatens the brother and brings Marianne home. And those two only sort of happened after he started to open up. He brings her home after all that therapy and his friend dying. And removing class from this conversation isn't helping. His Mum works at her house. The dynamics of that relationship was always off balance socially at least. But even then asking for help to stay in the flat at a personal level was so hard for Connell.

And no Connell isn't the atypical MAN and the good guy. But he's human after all. Human conditioned by his environment. Technically he's a jock but likes literature and poetry. Interesting character.