It sounds like a nightmare OP, and I hope that your DH manages to get some more good nights of sleep.
I work in an NHS hospital which does have single rooms (each with ensuite bathroom). We often have patients who are confused, have a delirium or a diagnosis of dementia on my ward....along with acutely ill patients (which is what my ward deals with as a speciality....the latter, not the former).
It is very very difficult to get even normal staffing levels at the moment (and it was hard enough before). In an ideal world, there would be adequate staffing levels....PLUS 1:1 staff allocated for the most confused patients. But that is a kind of utopia, particularly now.
The single rooms are (IMHO) fab: I think it does a huge amount for a person's privacy and dignity to have their own "safe space" and their own bathroom etc. However, we still get complaints about them! Many patients don't like how isolating it can be, and prefer the old Nightingale style wards (that's how things were when I started working in hospitals) or bayed wards. What one person prefers, another person hates. Another problem with single rooms is that a staff member can only be in one place at one time...therefore, if I'm tending to an acutely ill patient in one room, I cannot see/hear the confused/aggressive/wandering patient who is absconding from their room and going into other patient's rooms. When working on a bay or open ward, I'd hear what was happening beyond the cubicle I was working in, even if I couldn't see it.
Before the pandemic (and when/if appropriate of course!), I often would set up table and chairs at my nurse's desk for confused patients. I'd make them cups of tea/coffee and give them small snacks, play them some music (on my phone!) and do an "impromptu tea party type thing". It meant that I could supervise safely several confused patients, whilst getting paperwork/patient notes written up. It also meant that the patients had a bit of social interaction, and maybe some sense of belonging. I used to love doing that....it was a way to chat with them (often very random conversations!!) and spend time with them, but also be able to keep an eye on them whilst being able to get other work done. No way could that happen now though!
With respect to your DH's belongings...is it worth getting him to ask the nursing staff to give him some of his printed patient labels to stick onto his things (phone, charger, tablet)? So that if the confused gentleman comes up and tries to take his stuff, DH can say, "ah no mate, these belong to me....see, they have my name on them". Sometimes, that helps. See if he can chat to the ward staff and see what they come up with. Please know that, yes we're busy, but we do want to do our best for each and every patient. x