I'm Lucy, and I'd be happy to answer your questions today. I'm sorry to hear that this happened.
Initially, it's up to the girlfriend to remove their belongings, either before or after the eviction. The mother can go in to pack up her son's stuff if she wants to help (assuming the girlfriend and son will allow it - you can't let her in without talking to them). But you're under no obligation whatsoever to store his stuff for the next 10 years.
What the law says is that a landlord must send a tenant a notice giving him 10 days to pick up his belongings after he moves out (15 if the notice is mailed). You can still mail the notice to the girlfriend. You can even mail it to the jail if you want. They have to pay the costs of storage before they pick up the stuff. If they don't, you can sell everything and use the money to pay your expenses associated with the sale and storage. The notice is laid out in Fl. Stat., Section 715.105. The fact that he was taken to jail doesn't change your obligations as a landlord.
If the girlfriend has filed for a stay, that will be addressed by the judge in court. She won't be allowed to stay unless she pays the rent she owes you. Since you already have a trial date on Monday, you wouldn't be able to get in any faster than that.
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