As others have said, the best thing your son can do is run far from this deal, buckle down, save his pennies (he probably already is doing this), house-hack, and improve a property with sweat, hard work, developing a DIY skillset, and self-managing tenants. 

If the fence is shared and in bad shape, framing it as a mutual improvement could help.

I had a tenant force me to pay for some dumb azz air quality test where she claimed my air was bad and making her sick. 

So as the new build went on, we focused on improvements to our first home and got it ready for tenants.

Plenty exist for private lenders (which is what seller financing is) and can track payments and am tables and also do automatic electronic withdrawal (ACH debit) which helps improve the likelihood of getting paid promptly each month.

They listen to what you suggest and continually improving their software and processes.

Consider increasing rent, refinancing, or switching to a mid-term rental to improve cash flow.

Looking to improve my investment skills, I decided to get my residential home inspection license which led to me starting HLC Home Inspections.

Despite only renting for two months, this tenant's aggressive behavior is creating a hostile living environment for other residents.Specific Issues:He complains about our lack of notice when entering the property during our own move, despite prior notification.He has moved items around the house without permission.His communication has been condescending and confrontational.He installed a surveillance camera in a common area, violating the lease agreement.He banged on the door because he couldn't use the smartlock code properly.Considered Actions:We plan to serve him with a notice to vacate.We are considering having a constable with us when we serve him the notice.Questions:Should we just give him warnings considering that his actions may not improve?

Are you looking to pay off the hard money loan, fund another investment, or cover property improvements?