very old cat + very big move

I'm not sure if this goes in health or care, but I'm posting it here because I'm mainly concerned about his health. Move if it's in the wrong spot, it's late and I'm freaking out a little.

Fluffy is a twenty-year old orange DSH. He was adopted at three weeks and lived in the same house his entire life. He was always opposed to strangers in the house. His house is in New Jersey where he lives with my parents. He's an awesome cat, we grew up together and were best friends.
Well, my parents are moving to Florida this year to take care of my sick grandfather. This is where I'm stumped and concerned. Fluffy is twenty and aside from age-related issues (arthritis is the only thing, and I think he's on a low-protein diet for slight kidney issues), he's a healthy cat. But this would involve moving him either via plane or a very long car ride (he *hates* car rides, just a fifteen minute drive to the vet and he's yowling piteously the whole time) to a brand-new place far-away where someone he has never met lives (and that person really doesn't like cats). 

I'm worried that he'll be so anxious and so confused and befuddled in his twilight years that he'll either die on the road/plane, or die shortly after arriving from the stress because he's...well, twenty.

I don't know what to do or how to advise my parents at this point as to how they can help him. I'm at a loss and it's making me really sad, because I care about this cat very much! We grew up together. And I can't take him into my apartment because we have a small apartment and already have three cats, all of whom are young fellows.

Any help would be awesome.

Well, the good news is that the warmer weather in Florida will likely help his arthritis. 

I've seen many cats raise a ruckus on a short ride in the car, but settle down after a while and do quite well.  He likely won't eat, drink, or use a litter box on the move, so be prepared for that.

Why can't they take him to Florida?  And why is the only option for him to go to a home with someone that doesn't like cats?

You can move him via car, just get a mild sedative and administer as directed. 

We have a 21 year old cat that we got when a family was tired of taking care of him when he was 18. There are people out there that will take in older cats, you just have to look really hard. Contact local no-kill groups and see if they have anyone that will take in an old guy, or would be willing to post a picture and description of him at their adoption fairs. 

It would be more stressful for him to go to a home with someone that doesn't like him than to make a move with his family. 

As I understand it, your parents want to take Fluffy with them, correct?  They don't want to give him away?  You are just concerned that he won't make the trip "happily", and that he won't be happy once he gets there?  I agree with Mike that once he gets going on the road, he will probably settle down.  We moved with 3 cats and none of them liked the car, but once we were on our way, we didn't really hear a peep out of them.  (now, at the hotel that was an entirely different matter )  Are your folks moving in with your grandfather, or will they have a separate residence, or will all of them be moving into a new place?  No matter which, really, THEY will still be with Fluffy, I'm guessing, so he will have something familiar.  And if they are moving with their furniture, he will still have lots of familiar scents around him.  Even though he is 20, he should be ok.  He might even like it eventually.  As Mike said, that warm Florida sun might feel might good on his arthritic joints!  (I would venture to say he would like that better than moving in with you and 3 "young fellow" cats!!, particularly if they're anything like my little guys.  My two 3 year olds (cats) are constantly running over my 16 year old as if he wasn't even there)