They took Caylee and Casey in and gave them shelter when Casey didn't want to be in her own family's home -- and this AFTER they knew Caylee was not Jesse's child. You can't be around a baby so much and NOT fall in love with her, regardless whether there is any blood relation. They didn't need a current or "viable" relationship with the As in order to be personally hurt by Caylee's disappearance and death and by Jesse's being wrongly accused for it.
I strongly assert that his son IS his business. This isn't a case of your kid getting a speeding ticket and making them stand up for it on their own. He was being accused of MURDER, for heaven's sake! You would not stand up for your child if he were accused of murdering a baby (or anyone else)?!?
Now, I personally do think Mr. Grund is odd, and at least in a couple of instances, his writings seemed to be about how certain things happened because he needed to learn a lesson (as if he's so special that those things were meant for him instead of others or no one at all)...a bit self-centered, IMO, and yeah, maybe a bit of a publicity hound, too.
However, first and foremost, he is a FATHER whose son was accused of the most heinous act imaginable -- murder, and murder of a child he once believed to be his own, a child that Jesse would always love! I certainly would not sit by and twiddle my thumbs while the As accused my INNOCENT child of murder, regardless whether he were 10, 30 or 60 yrs old!
I think RG and Jesse both have shown incredible restraint in what they've said. Jesse, bless his heart, going over there trying to HELP the As, even after all Casey had done to him and knowing the family didn't like him. He's a good-hearted young man. Just trying to help, and all the while they were trying to figure out a way to pin it on HIM.
That's one reason I have so little sympathy now for the As. Of course, I will always feel sorry for them for their loss and pain; but I can't feel sorry for someone who would try to pin a murder wrap on an innocent young man -- especially one who was trying his hardest to help them -- just to save their own kid from what she's done.
You might be content to let your adult son suffer it on his own, but I would NEVER butt out of defending my son from disgusting and malicious allegations of being a baby-kidnapper/murderer.