I suggest it because he's doing the typical newb thing. That is, signing up and posting a thread asking whether he should purposely screw with his body. I just don't want people making hasty decisions that they could seriously regret.
There has been NO proof ever that wearing 24/7 will make you incontinent. I have no idea why people think it will when there's no proof of it at all. In fact just the opposite is true, what do people wear up till there two to 3 years old, diapers. How often do they wear them, 24/7. Can they be potty trained, of course they can't.
It would relax his sphincter and possibly make it hard for him to hold himself, depending on how long he uses them..
Go for it. It'll be expensive, but since you already wear to bed, and it's highly practical for long-distance driving (sometimes encouraged), there's really no reason not to. As said before, you'd only have a few hours, if that, to go with underwear, but you could choose to switch between them anyways.
Remember that going 24/7 is one of the only ways to train yourself to be incontinent. It is NOT a guarantee that you will become incontinent just because of that fact. If you want to retain your control, you will!
Besides, you're on this forum, meaning there's a good chance you'd enjoy it anyways.