There's a couple of ways to go about handling this. First, you need to be careful about your mother's registration. Florida
is usually pretty active with their registration and if she drops coverage, she risks having her registration suspended and the possibilities for fines. In this sense, dropping coverage isn't really an option. I recommend having the aide added to the policy (if she will using the policy regularly) and transitioning your mother to the "additional interest." Because your mother's aide will be using the vehicle often, she needed to be a listed driver - that's the best way to ensure she will be covered using your mother's vehicle. There is a clause in many insurance policies known as "permissive use" - which allows infrequent drivers the ability to use the policy without having to be added to the policy. However, it sounds like your mother's aide would be using the vehicle more often than this. This remains the same for anyone who uses the vehicle often - you and any siblings you have. I would contact your mother's insurance company and see if they have any company specifics for situations like this. However, it will most likely be similar to what I have outlined.