My husband is bladder incontinent. No matter what tab style brief he uses, he often wakes up with a wet t-shirt, and sometimes wet bedding due to urine leaking at the top of the brief. I suppose he urinates at night with his penis “pointing” up towards his navel. I cannot find any solution for this anywhere.
I don't have any experience with men in diapers over the age of two, but it's worth a try, combined with an extra pad.
https://www.amazon.com/Top-Incontinence-Pouch-Level-Pack/dp/B015WR7X0U
There are also condom catheters - those are pretty much just what you might imagine them to be.
You may also have to get up a few times over night to change him so he won't be so wet in the morning. Also make sure that you have several waterproof pads under him, so if one is wet all you have to do is pull it out from under him and he will be on the clean one.
My husband was severely incontinent for the last 4 years of his life, and after trying all the bladder spasm medications and having Botox put in his bladder with no success, his urologist recommended that he have a supra pubic(permanent)catheter put in which was a Godsend for sure. I then only had to empty his catheter bag once in the morning and once in the evening, which made life easier for us both.
Good luck in getting this issue figured out.