He was someone who didn't know how to make decisions for sure. All characters need flaws but his had such a big impact on other peoples lives.
He had the same resources later in life in his past life as he does now. All the events in the past are the same up until they both reawaken a bit before Elle is born. In the flashback he is shown showing concern for the FL and Elle while she was in labor, and then he went back to the norm of ignoring her. In this timeline he is trying to change.
What makes him unlikable, maybe even unredeemable to me, is that fork in the road. He was so riled up that he pulled out his sword and threatened one of the doctors that they shouldn't let her die. And then....nothing. She was able in this life to dismiss all those shitty servants like it was nothing. Surely if the father in law's treats were real then he would have had some spies within those servants. But either there was no push back, or the writer is (hopefully) gonna use that push back to big effect later in the story. The ML mentioned that his ex fiancée was in league with the father in law, and that the father in law kept positioning her near him in order to torture the FL. But in this new timeline the ML and the Fl pushed back against the ex fiancée in public at that party. So far no negative consequences from the all powerful and scary father in law. To my remembrance we've seen the FL once in this new time line and he was still taking the same bull shit. At least his son/her brother pushed back. I just hope that was some foreshadowing for future actions.
The father in law HAS to pull some shit in future chapters in order to complete the story and really give the ML a true redemption. Otherwise previous timeline him was just an easily swayed person that never thought of using his newfound power to push back and do the decent thing. Not even for love, just decency.

Because right now both the FL and the ML are living life the way the want too. The Fl has no reason not to live her second life to the fullest. But if the ML can just do whatever he wants now, then why was he so scared of the father in law in his past life? They went back in time but I think it is safe to assume that they both returned shortly before Elle was born. Which means that he should still be under threat from the father in law.
They need something big to bring them together, or at least to get them talking about what happend in the past. The father in law is the best thing to do that. It would make the ML look like less of a coward in his past life if the father in law actually does something threatening in this life. Because other wise he ignored her to the point of getting back with his ex fiancée and letting her die alone just because the father in law threatened to take his dukedom away, and to kill the FL. Well his son rebelled and joined their country's enemy after learning the truth, so their goes your dukedom. And she died of sickness and heartbreak while you did nothing, so did you even care about her life at all? If the father in law can't actually take away his title(or at least doesn't try to take the title away). Or if he doesn't try to assassinate the FL, then his sob story is just like...Dude you got played in your last life.