He’s been rejecting him for a while
He wants nothing to do with his donor
He’s in great health with a great job so I don’t understand why all of a sudden he’s coming around for

I think your son is doing what’s right for him right now. That’s a lot to process at any age and it’s very common that absentee parents show up that 1-2 years before the kids turn 18. Donor needs to back off and give him that space, period.
But, how is donors health? People who suddenly get a heavy health diagnosis of some sort will go out and try to right their wrongs so to speak.

Because the hard part is over. He doesn't have to raise him. He doesn't have to change diapers, bathe, feed, etc.