What causes fingernails to do this?

My husband's grandfather is really old and his fingernails are coming off of his hands. In other words, you can actually raise the fingernail and look underneath it.

The only things I could come up with is either a calcium deficiency or some type of fungus. Any ideas?

I wanted to add that he has cancer from which he will eventually die and wondered if some of his meds or the cancer may be the cause.

It called onycholysis and its usually caused by a fungus. If his nails are thick, yellowish and spongy on the underside its definately a fungus. He could go see a podiatrist and get the nails removed if its bothering him but there really isn't a viable cure for someone his age. The topical treatments simply don't work and the pills are are really hard on your body. A nail fungus is unattractive but certainly isn't going to kill you or even make you sick you can live with it with no problems.
If he doesn't have any of those ofther symptoms, it could just be caused by age or medications he taking. Its not common but not unheard of to get nails lifting of the bed with no fungus.

That is a fungus problem on his fingernails, it can be treated and it has worked, a friend of mine had that, and he went to mexico and got some cream and some pills. he was to file his fingernails and put that cream and take the pills, and to keep doing that for a month or two, then they went away. Report It

Stop lifting up his fingernails - and call his doctor.

Take his grandfather to the DOCTOR!!

(Edit)

Ummm...yeah...still go see the DOCTOR!!!

fungus

It could be an infection, fungal, bacterial, something internal. It's probably a symptom of something going on inside him. You need to bring this up with his doctor.

Cud well be fungal infection. Try Lamisil cream - worked v well for me