Start by telling him he needs to leave or pay and post the proper paperwork. 

Suggest treating the areas and possibly installing sister boards to firm up the beams.

Or as my wife likes to call it: "man-sitting"Contractors unwilling to execute on what you hired them for (I.e. current flip, cabinet installers were supposed to put up fill and crown.  

And you can actually use those funds to invest in properties or do lending, if done properly. 

Provide the tenant an option to install a security system at a cost to them, since there are no police reports about break-ins. 

We added value by re-doing the whole house, installed vinyl floorings, rebuilt 2 and a half bathrooms, re-painted the whole house, replaced all the hardware in the house, installed new lighting, ceiling fans, re-painted the kitchen, and completely remodeled the upstairs.

I too would look into a fence installed by a professional and ask the tenant to share the expense. 

Take ownership of your mistake and learn to do the proper due diligence recommended above😊

If you are not in Huntsville or Madison proper, you may want to wait out things for a minute, as some of the outlying areas are definitely tilting toward supply exceeding demand now.  

This includes things like cutting down the grass and installing a drain in the basement.