I've had a joint account with my mother since my dad died in 2009. Can I use that money?

Use that money for household expenses, and you will be fine. Don’t use that money for clothing or jewelry for yourself though until she passes away. If she needs caregivers or needs to go into a nursing home, that money needs to be used up before she can apply for Medicaid.

It’s a joint account for each of you to use. I assume that you are using it to make purchases and payments for your mom. I wouldn’t use that account for your personal use until your mom dies.

My mom also lived with me for 14 years. I was on her checking account because I did all of her shopping and paid for her cell phone, etc. I didn’t use it for any of my personal purchases.

103! Wow! My mom died at 95. I just lost a cousin who was 101.

"The money in joint accounts belongs to both owners. Either person can withdraw or spend the money at will — even if they weren't the one to deposit the funds. The bank makes no distinction between money deposited by one person or the other, making a joint account useful for handling shared expenses."

Source: https://www.bankrate.com/banking/what-is-a-joint-bank-account/#how-do-joint-bank-accounts-work

It will be all your money once she passes. But if she ever needs LTC before then (which is covered by Medicaid) you must be very careful what you do with that money. In most states the Medicaid "lookback" period is 5 years. Maybe consult with a Medicaid Planner for your home state.

https://www.investopedia.com/terms/j/jointaccount.asp

No, its her no money and should be used only for her.