Is their a service that will come to home for 3 hours about twice a week to sit with person that cannot be left alone?

If the person qualifies for hopice, they can get respite care from the hospice service

Sharon, one suggestion would be to contact your local council on aging.... click on the link that is posted below.... now click on your State... now click on your city/county. Hopefully they can give you a list of groups that could help out.

https://www.agingcare.com/local/Area-Agency-on-Aging

Home healthcare will come to your home to sit with your loved one. You'll need to find an agency in your area with a Google search.

In my community there is a volunteer service for this. Such a service may also be a benefit of some programs. Is the person entitled to VA benefits? How about Medicaid? Is the person on disability? You might want to start by contacting the Area Agency on Aging in your state, to see what is available.