What an adult does for themselves is irrelevant. Many adults live in conditions that are not suitable for children, but they are adults, so up to them
This is not compleatly true. One of the things being assesed is if there is a difference between how the children are treated and how the adults are. Beds can be a very good indicator in the differences in care.
If parents have a nicely decorated and furnished carpeted room with a nice made up bed in it and the room is clean but the child has a very sparsely furnished uncarpeted (or any flooring) dirty room with very differnt standards of bedding then you often have a much bigger problem than if both are much the same.
On a different note (not withstanding that this appears to be quite different because other things like dental decay are a problem. I once knew a family whose child never had sheets or duvet covers always slept in his day clothes, it was hard to get your head around it but that child had the cleanest bed I have ever seen and started each day immaculatly clean and well turned out.
He has sensory issues that meant he couldn't tollerate sheets or duvet covers or blankets and with them on the bed he just wouldn't sleep or he would get out and sleep on the floor. He also hated PJ's.
His parents replaced all his bedding twice a week and his matteress twice a month and I do mean brand new stuff (they tried washing it all but he couldn't cope with how it changed the feel).
They were able to stop replaceing the mattress so frequently when after an unexpected hospital stay as a teenager they discovered he liked hospital mattresses and they are steam cleanable. So now he gets a new one of those every year.
His day clothes were 7 identical track suits worn over thermals every morning he would have a bath have a fresh set of both and he would stay wearing them until the following morning as he couldn't tollerate getting into bed with fresh clothes.
All this talk had just reminded me of how privileged I was to have met that family