first of all : lyall and hope lupin are the most loving couple in the world. i think most of wizard/muggle couples are because they were trusting enough to tell them the truth, but hope and lyall are particularly close. they trust each other and forgive each other. they are just perfect for eachother and every one knows it as soon as they see them together. they share a sweet and soft love that nothing could ever bring down.
about remus : before he was bitten, he was closer from his father than his mother. he was very close of hope too, but his dad was his personnal hero, the man he would dream to become one day. they have many things in common and share a lot of stuffs, even though lyall is often at work.
but after the attack, things change. remus doesn’t know the circumstances of the bite yet, so he isn’t mad at lyall. but lyall is feeling terribly guilty, he thinks his son is better off without him. the only thing that stopped him from leaving the house was hope, who tried to make him feel like it wasn’t his fault and they still loved him. it still takes years for him to get close to remus again, but their relationship is changed forever. he loves his son with all his heart, but he hates himself.
so remus gets step by step closer to his mum. since she’s a muggle, she doesn’t have the same predjudices against werewolves than wizard. because she started to believe in magic so oh sure, she can believe that werewolves are nice most of the time. and since remus can’t do loud games outside with his friends anymore, he starts to appreciate his mother’s quiet presence. she’s the one that introduces him to books, and shows him all her favorite movies. she is the first to call him “professor lupin” because he always tries to teach her things he read ( most of the time she already knows them but she plays along and pretends ). the two of them are as close as a child and his parent can be.
remus cannot even understands the concept of parents not loving their child with all their hearts.