Recommendation on a single bed for my elderly father?

Does your dad have any mobility issues? If so, a hospital bed would be a better investment.

Do you already have a bed frame or were you planning on buying one?

Have you talked to an Occupational or Physical Therapist about what sort of bed would be best?

Medicare will pay for at least part of the cost of a hospital bed if scripted by his doctor.

Why don't you want a hospital bed, it would meet more than your criteria and save you from having to look again if/when the need arises - one of my peeves during the years I cared for my mother was that I wasn't advised to buy with future needs in mind so we ended up spending more for upgrades. You can usually find barely used hospital beds second hand and just buy a newer mattress.