It can vary a bit from place to place. Most places do have an older people's mental health ward but sometimes they are mixed (general mental health and dementia) and some places have separate wards for each.
The wards are in many ways nicer than a general hospital, you usually have your own bedroom, many places ensuite, there will be a day room, dining room and often an activity room. Some places have secure garden spaces too so people can safely get a bit or fresh air.
There are usually activities, some will have a specific staff member to arrange these, access to an OT as well as the nurses and support workers. There should be a meeting "ward round" at least once a week which you can probably join remotely (on teams etc.).
The nurses will observe and record any behaviour changes and report this back to his named psychiatrist, they will make sure he has any medication he needs, they try to avoid over sedating people (but sometimes starting a new medication can make someone more tired). They should be able to update you if you're worried.
If you search for the hospital some websites have a bit of a guided tour of their wards so you know what to expect.