Besides outing him to his parents (instead of urging and supporting and helping him find the strength to do it himself), I thought that bad-mouthing Michael parents in front of his son and Michael himself was definitely, to use an old phrase, infra dig (beneath dignity).
I think if you do things that are shitty, then you reap what you sow as far as Michael's parents go.
You could see Michael was feeling uncomfortable. They are Michael's only parents, and they are the child's grandparents. What's to be gained by humiliating them, maybe even as they are trying to come round?
Who says they are trying to come around? They sound like opportunistic people to me. I'm not a fan of anybody that wants their gay son to marry a woman and I won't defend them.
It seems to me he's trying to make himself Michael's parent.
I think Michael needs guidance in his life and so he will probably attract a partner that will have some parental qualities. Michael seemed a little slow to me.