How do we add a co-owner on to deed of property?

Bad idea:  inherit the house subject to Medicaid Estate Recovery and, if your mother needs a lot of nursing home care paid for by Medicaid, get little or nothing. Worse idea:  hire a lawyer to draft a deed from your mother granting you an interest in the house "with right of survivorship" and, if your mother needs to apply for Medicaid for nursing home or home health care (Star + Plus Waiver), both be charged with Medicaid fraud and, at a minimum, have to deed it back (both the Bexar County DA and the Texas AG could get involved) Better idea:  hire a lawyer to draft and record a revocable General Warranty Deed Reserving an Extended Life Estate (a/k/a "Lady Bird Deed") from your mother to you or let your mother sign and record a revocable Transfer on Death Deed (www.texaslegalhelp.org) transferring the home to you on her death and free of Medicaid Estate Recovery.  In Texas, Medicaid can only recover from the probate estate.  If the deed transfers on death, the home never becomes part of the probate estate.