Whatever happens, I'm glad Kyū is in their lives even if being stuck in this situation seems hard on him. I can hope that maybe they can be a happy family someday and that Mahiro gets the love he deserves. He's a good kid, and he definitely doesn't deserve to be in the middle of what's going on with his parents.
(I'm also going to play Weeping Cherries at some point. I'm curious about how that story differs. I'm hoping there's a happy ending for Kyū in that one!)