If I try to be more positive about this, I'm suspicious it's a cooperative ploy by Saki and the dad. Something like the dad had love-hate feeling to her son. He hated that the son's birth make him loses his wife, but it's still the son of his love. Things like awkward redemption to his son. "I'm sorry son, I'll give you a mom now." lol. The dad also seems to be depicted to like to be at the altar of his late wife.
Saki is weird, but if it's really just an unconditional motherly love, I had to praise that. But I kinda doubt, remembering that Saki was in that milf app...
All in all, just a trio of morons lol