I'm in a very similar position OP. And it sucks. Big time.
DF88 lives with me and has a condition that comes under the Parkinson's umbrella but it's not the same thing.
He'll do one wee when I get him up at 8am and he doesn't do another until 8pm. Bed at 9pm. He wees a LOT during the night.
A year ago he had a temporary in-dwelling catheter for an unrelated problem. It was in for a month. It was interesting to see what his urine output was. During the day was 200mls. During the night it was 2000mls. He no longer has the catheter but this is still his pattern.
So what do I do at night? He can't get out of bed unaided. (He can't do anything unaided.)
To start off with he had a urine bottle by the bed and he'd wee in that. Then it wasn't enough so he had two. Then he got too shaky and he'd drop them or they'd fall on the floor. Nice surprise for me in the morning. Then he'd get too confused and think he was weeing in the bottle but he wasn't. Then more of the wees came while he was asleep and he didn't even attempt to use the bottles.
We use a waterproof mattress protect. A sheet. A disposable bed pad. (Tenna bed mats with wings). The NHS don't supply these. I get them from Amazon. I found the washable bed pads didn't hold the wee in one place and the spread was too extensive.
After dicking about like this for a couple of years, he relented and agreed to use an incontinence pad. The continence nurse gave us a few to try. They're all as awkward as each other. We settled on one and have the highest absorbency possible. We've gradually increased but now have 4 per day/24hrs which is the max we're allowed. They come 12 boxes at a time so I have store the buggers!
So. Bed time. He wears pants to keep one in place in the regular position. (Willy MUST point down.) It leaks because they lie when they say they hold 3000mls. So I put another lengthways round the back, still in the pants. I put a third lengthways across the front, still in the pants. I put two underneath him cos they're free and the bed mat isn't.
This works relatively well until he forgets my master plan and tries to get his willy out anyway. Or only half gets it out but it's left pointing up. Then he wees all over himself and the bedding.
It's a 4.5 tog duvet so it fits in the washing machine and we add blankets during the winter.
Although this means he's in a damp pad all night, it is what they're designed for and like baby nappies, they draw the moisture away from his skin (although not as well). It doesn't smell like it does when it goes everywhere. I use that cleansing foam (I'll add a link) they use in hospitals and care homes to clean him up in the mornings before getting him dressed.
He HATES the shower! So far his skin is coping ok but obvs I check it daily. We had a flurry of attention from district nurses after his hospital stint last year but they all fucked off in March when covid hit and I've not heard a dicky bird from anyone since then.
I'm not sure where I'm going with this anymore. I don't know what the solution is, for you or for me.
I might explore what was suggested up thread about medication to reduce night time urination, but I've mentioned it before and nothing was forthcoming.
Our only saving grace is that my mum died 12 years ago and was spared all of this :( I gave up work and look after him full time.
Vernacare Senset Cleansing Foam -... https://www.amazon.co.uk/dp/B01I3XU640?ref=ppxpoppmobappshare
Conti SoSoft Large Heavyweight... https://www.amazon.co.uk/dp/B00J3UMQXC?ref=ppxpoppmobappshare
Tena Bed Plus Wings - 80 x 180 cm, Pack of 20 Sheets https://www.amazon.co.uk/dp/B0099QEZT8/ref=cmswwrcppapifabt118YLRFbG17JHHB?encoding=UTF8&psc=1