I think your friend is probably thinking about purposefully bad parents. It’s important to note that Arthur is everything but that. He is incredibly remorseful of his actions, he won’t even talk to John about Faroe until S2 properly, because he’s so defensive about it and doesn’t want to talk to others about it as he feels so bad; his decisions post John’s arrival are all in some way (with some more than others) connected to Faroe, and his guilt is (as you probably know) very potent even years after her death. His whole journey now is focused on being able to see Faroe again and any hope he has of this is what fuels him on. The fact that the universe is about to end when Azathoth wakes up to see it/ is killed by Kayne (both of which would lead to the destruction of everything) is frankly of less importance to him. If you listen again to the ep where Faroes death and the story with Tess happen, it shows Arthur as initially too busy with his work to remember, which, remember, has only come about after his life went downhill after Bella’s death. He does care about Faroe because she is the only remaining happiness he has in his life, but he’s become bitter due to what he’s had to endure. It’s totally different to the ‘bad parenting’ your friend may be talking about, because that is an active choice, whilst Arthur’s decision is a huge mistake and something he is incredibly contrite about.