If I were you, CrazyClean, I would stop doing all the clearing up of the wet bed - your OH needs to step up and do his share of that. I would recommend getting a good, waterproof mattress protector (or maybe even two), so that you can keep the mattress dry. Boots do good ones, if I recall correctly.
Ds1 went back to bedwetting at 7 years old, and it carried on for several years. In the end, we used a bedwetting alarm, which did almost completely solve the problem - it went from a nightly occurrence, sometimes more than once a night, to occasional.
We also found it helped to 'lift' him, last thing at night (we usually did it around 11pm - midnight, just before we switched our lights off to go to sleep). I know that it isn;t always recommended, because children often end up weeing half asleep, when you lift them, and that isn't a good habit - but on a purely practical level, it did help reduce the number of wet beds, especially once we'd used the eneuresis alarm too.
I don't know if you have talked to the boy yourself, or whether you are waiting for his dad to step up - but if you haven't, I think I would start a conversation with him yourself, and explain that it isn't nice to sit around in urine-soaked clothes - for him or for anyone else who has to cope with cleaning up after him - and that what you'd like him to do when he gets up is to take off his wet pyjamas and pull up, and have a wipe with some baby wipes, then put on clean underwear, and either get dressed or put on clean pjs. You could put a washing basket and a pedal bin in his bedroom, so he can put the wet clothes and pull ups in them.
Explain it will be more comfortable for him, and you know he is a big boy who can do this - no criticism, just a set of practical advice for him on how to cope.
Ds1 did eventually grow out of his bedwetting. Because he was older, it was considered a medical issue, and we did have some advice from the local Eneuresis clinic - but what actually solved it was hiring an eneuresis alarm (via the internet, iirc). We did carry on lifting him, for ages after using the alarm, because we thought it helped prevent the occasional wet bed that he did still have - but eventually bit the bullet and stopped lifting him - and he was completely dry from then on.
I am sure that your dss will be dry in his own time - but in the meantime, his parents need to step up to help him deal with it - and your OH needs to help you with the necessary cleaning. And if they won't teach him how to look after himself and clean himself up, I think you need to. In a kind and caring way - but someone needs to do it.
Apologies if you have already explained to him what he needs to do.