How to handle excessive spending from someone that is in the early stages of Alzheimer's?

What I had to do was put a limit on mommas credit card but what she was doing was giving it to one of the siblings to say go buy me two packs of cigarettes they would and then buy their own cigarettes and there wife's and anybody else's. OH and then they went to Walmart and bought dog food and anything else they needed and then to the gas station all on mommas card. Go back and give momma her cigarettes but didn't tell her they charged an extra two or three hundred. Her monthly cc bill kept going up every month. I had to control it and then when momma went into assisted living the cc disappeared.

My aunt went on spending sprees. She would order tons of stuff from the shopping channels. She said that she needed new outfits to wear to church. She maxed out credit cards.

My uncle decided to get a separate card (debit) and set a limit. She could only shop with the new limit.

Best wishes to you.

You can go to the bank, put a limit on the card. You can also create a separate, new account with limited funds. In such situations, you might have to go ahead without asking her permission.

“Hey sis, the bank gave us this new card. It’s safer than the old card.”

It may be at the point where you need to step in and manage your sisters affairs.
And if she is living alone you may have to have this discussion with her as well.
It may not be safe for her to be living alone.
There is no easy way to do this and she is not going to like it.
The fact that you are so distant from her you do not really know what other problems she is having.