I’m sorry I have no experience of Almhouse accomodation. All I can say is that it is very hard to find social housing these days and if they have a chance to move to somewhere they want to be, they are quite lucky. If their needs change, the fact that they are in social housing should help them with a transfer to more suitable accomodation ( eg sheltered accomodation or nursing home) when/if it becomes necessary.
Also, the trustees have no responsibilty for entertaining the tenants but they are no worse off than the rest of us who have to join U3A or other clubs to make acquaintances. Is the almshouse handy for easy transport to town etc? If they have a pet they will need to know if that is allowed, but I expect they have done that. Any rented accomodation has some restrictions. You or they, could knock on a few doors in the development and ask the tenants if they are happy there!