You are wrong. On all accounts. Period.
1) parents may or may not have indulged him. They let him come back and live at home at age 22. That's not so indulgent. We have no idea if they have been asking him to get a job or what they agreement or interactions were like. You don't know. I don't know. All we know is they started on October to talk about him moving out. In February they made it official. It's their house. He's an adult. It's perfectly within their right.
2) From a legal perspective, the parents won. A NY supreme court ruled in their favor. Did you read the story? The judge sided with the parents and he needs to move out. Again, it's their property. Not his. He's an adult. Many times over.
3) Marital property is joint property. If your wife divorces all property in the marriage is joint property (depending on the state and any pre-nuptial agreements). You and your spouse can agree on how to split the property. You can hire lawyers to negotiate the split. Or a judge and split it for you. This may result in the wife getting the car. It may not. It is not a gift. It's joint marital property. This is not at all similar to the slacker 30 year old.
4) A housing situation is not a gift. You don't gift a room in a house. You may gift property. Or you may gift a partial ownership in property. There has to be indent. There is no evidence the parents intended to gift the property or a portion of the property. The son is a tenant. All he needs to sufficient notice. The judge agrees that the notice was and is sufficient. The son is required to move out. Immediately (since he was already given notice).
Did the parents fails him. Yes. But parenting is really hard. Despite your best intentions, dealing with children is not an exact science. What worked for you may not work for your children. What works for your neighbors may not work for you.
What's is best for Johnny now? To get kicked out and make it on his how. He's 30 and has not worked for 8 years. There are jobs. He can get roommates. He can live in his car. It appears he has been refusing to work because of all sorts of excuses that all generations up to and including baby boomers love to make. I have my own business (which is clearly not making him sufficient money. Get a job and do your business on the side). I don't have time, because all my time goes to getting my son back (I'm sure a big reason of losing joint custody of your son was your inability to support him. Get a job). I can't take too much money or help, because I need to prove I'm poor so I can get my court costs covers (Really? Really? Get a job. Get a freaking job, you bum, and get out of your parents house. And get off my lawn!!).