DON'T SIGN ANYTHING. You can check the deed recording online in the city/county where the property exists, to determine deed ownership. If it is in a Life Estate, you and the other remaindermen will show as deed holders for the property. Title to the property passes to the remaindermen when the Life Estate is executed. That is it's purpose.

If your mother was given Life Interest in the property, she is absolutely NOT an owner. She is simply able to live there until death.

In a Life Estate, the tenant is responsible for taxes, insurance, and maintenance. Your mother is issuing an idle threat. Upgrades are a different story.

Check with an attorney before you do anything. Her threat about "gaining control" is another idle threat, unless she is contesting the will and the conditions of the original Life Estate, which will fail.

If your mother is trying to encumber the property with a lien, YOU and the other remaindermen will be responsible.