I need to know who to call to see if my uncle qualifies for me, his niece, to get paid as personal assistant for him.

Your uncle can pay you State programs won’t pay a personal assistant. Did you mean a caregiver? If so...In order to be paid by anyone other than your uncle. He’ll have to be both low income and medically needy.

I live in Sacramento CA and it's through Sacramento County called In Home Support Services (IHSS).  Your family member hires you, you fill out a timesheet and submit it to the County and get paid.  Of course, there are income restrictions so you'll need to know how much their income is.  I believe it's through the department that handles welfare, child/elder abuse, etc (sorry can't think of the name of the department).   I would search your local county website.

If you search this site, you will find dozens and dozens of posts in regards to getting paid to be a family caregiver. But the honest truth is that, unfair as it seems, the Government doesn’t pay out much to family caregivers. I believe if he is on Medicaid, you might have a chance in some states, but even then the aid isn’t much, and there’s no health insurance or retirement fund unless you contribute to a fund yourself. If you draw up a Caregiver Agreement, ideally with the help of an attorney, he can pay you out of his own funds. But again, unless he is wealthy, it probably won’t be enough to live on. For further information, you can contact your local Area Agency on Aging.