Samadhi is of many different kinds. Broadly however there is a Samadhi from which one returns back. Here obviously nothing special is required for the care of the body except that it should be a place where there is no external danger. But there is another type of Samadhi in which one loses complete contact with the body and the outer consciousness. If one remains in that for long enough, a few days, then the body dissolves of itself.
There is of course a waking Samadhi but your question doesn’t concern that.
Affectionately,
Alok Da
