I see the whole phrase -- "one being that the patient is in their own
home" -- as a nominative absolute phrase.  So "being" is the is a
transformation into a participle of "One is that the patient is in their
own home."  "One" is of course the subject of the nominative absolute
phrase. And "that the patient is in their own home" is a noun clause
functioning as subject complement to "one."

On Wed, 24 Jun 1998, EDWARD VAVRA wrote:

> In the sentence:
>
> There are several factors that strengthen or add to this relationship, one
> being that the patient is in their own home.
>
> How would you explain the function of "being"?
> Of "one"?
> and of the 2nd "that" clause?
>
> Thanks in advance for your responses.
> Ed v.
>