Inherited A Squatter

Location: Florida

I’m a first time homeowner and I recently purchased my grandmother’s house from her and inherited a squatter/ tenant.

My uncle has been living on the property for the last 25 years without a written lease agreement. At first he was paying rent but stopped paying about 7 or 8 years ago. In the beginning he was living inside the main house but he moved into a studio apartment he added onto the garage (the apartment never had permits pulled for any of the work done).

He used to have hot water but the water heater broke about 10 years ago and he won’t let anyone into the apartment to fix things. He used to have a kitchenette setup with a hot plate, microwave, and fridge but no one’s been inside to see if that’s still the case. Instead he’s been coming inside the main house to use the shower, laundry and kitchen.

He does get some mail at the house but his legal address is a house he purchased 3 years ago about 15 minutes away so most of his mail goes there (he is claiming a homestead exemption despite not living there). He won’t move into it (it’s livable, furnished and he’s renting a bedroom) and he keeps making excuses for why he can’t move out yet. He has a ton of stuff stored in the garage and an entire locked shed that he won’t leave without and no one else is allowed to touch or he flips out. Instead he’s been taking a box or two every few weeks and claims he’s moving out as fast as he can. His latest claim is that he’ll be out by the end of the year.

I know I can’t do a self help eviction and lock him out of the apartment but can I change the locks on the main house so he can’t just walk in and then start the formal eviction process with the county?

TLDR: Bought a house with a tenant living in a studio apartment that doesn’t have a written lease agreement and hasn’t been paying rent. They had access to the main house to use the kitchen, shower and laundry, can I change the locks on the main house before evicting them?

Edit: I already have an appointment with a lawyer scheduled but it isn’t until next week.