Conservatorship for elderly demented mother?

My mother-in-law is demented, ten years now. She is in a nursing home and is on hospice, but really has no overriding medical problems (no high blood pressure, no heart disease that is documented, no diabetes). She is 85 years old.

We just moved her from Canada (she is dual citizen) to the USA. She was hospitalized briefly for urinary tract infection. Until then, we had been paying all her bills in the nursing home. Apparently, the hospital visit triggered application for Social Security, Medicare, etc.

Several months thereafter, we got a call from the nursing home, her bills had been paid retroactively, and we had a sizable check waiting for us, paying us back for most of what we had paid to the nursing home.

Recently, we received a check from the Social Security Administration. It is for quite a bit of money, it is in her name. She has no checking account. My husband checked with an elder law atty and since she is demented, she can't give power of atty for financial matters to anyone. The attorney basically told my husband he can't do anything until his mom dies, intestate, and wait for the probate courts.

She may not die soon, she is still pretty feisty and witty.

He is the only child. Her husband is long dead (20 years) and her eldest son is dead. The check is good for one year.

Does anyone know of laws (Texas) regarding how to deposit that in her name? We don't need the money, but don't want it to be lost. Can we apply to have someone at the state be her conservator and deposit that money in her name?

Any thoughts on this would be welcome.

Thanks in advance.