My dad had a massive stroke and is in a vegetative state. How can my mom get power of attorney if he can't sign his name?

Your mom will need to be appointed guardian and conservator of your dad. For this, an appearance in court is needed, thus she will need the assistance of an attorney. There really is no other way for her to get control over his assets and his personal and medical decisions.

Obviously, Dad cannot sign a POA if he is a vegetative state.

Have you talked to the SW at the NH? Much depends upon the laws of your state. Do you have a family lawyer?

If dad needs medicaid to be able to stay in the NH as a permanent resident, please know that the family home where mom resides does NOT have to be sold. You need to talk to a certified eldercare attorney who understands Medicaid in your state to figure out next steps.

I'm so sorry that you are going through this sad time.

I agree with Barb. You can't afford not to go to an elder attorney who understands Medicaid law for your state. Are you in California? My friend called the area on aging for her sister who lives there in Orange Co. They sent out a social worker who helped get her sister in touch with Kaiser, whose rep also visited and helped the sister get going with doctors and therapists.
About the POA. Your mom won't be able to get POA unless your dad regains his mental capacity. If he does and still can't use his hand to sign a document, there are ways to receive his agreement. Do not sign anything as a guarantor for your dad and don't allow your mom to. Please see a qualified elder attorney to protect your parents.

What kind of property does she need to do something with? Is this property in his name only? Are you sure she needs POA to handle this?

Consulting an attorney who specializes in Elder Law (the specialty is very important) will be worth the cost. Mistakes at this point can be costly.

There are emergency guardian procedures, the nursing home may be able to help with that. An attorney would be best. Call the Area Agency on Aging for help on where to go and what to do next.

Please call the local area of the aging. Where I live, there are law professors/lawyers at one of the local law schools that provide elder care attorneys for free to people over 65.

Listen to all the above and don't make the error I did of writing checks for my husband's hospital bills from my checking account, figuring I could later reimburse myself from his accounts. The hospital now claims I paid out of my own free will.

Definitely, don't do anything or SIGN anything until you talk to an attorney that specializes in Medicaid. That's a very important distinction. I reached out to elder law attorneys & found that there is a BIG difference. They must KNOW the process/experience navigating it and not try to "learn as they go".

Have the treating doctor declare him incompetent. This form should be filed with the county where he lives. Petition the Court for guardianship & conservator. Contact the social worker in the facility where he is being cared for. They will help you fill out all the financial aid forms to apply for Medicaid. Where I live you have to provide 5 years of financial records to make sure you are not hiding assets to get aid. The home is not considered an asset at this time. Is your mom's name on the title of the house? They will not displace your mom. Do not sell the house because the money then becomes a liquid assets and they will use all that money up before they assist with finances.

See if your state has a DADS website (Dept of Aging & Disability Services). They can help you find a state run Nursing Facility or intervene if you have problems with your current situation.