As others correctly noted, as a landlord you must look at the big picture and if this happens to be a good tenant who has occupied the unit for a while, has a history of timely payments and has expressed interest in remaining at the property the value in an extension (assuming that is advantageous to you as the landlord) should be placed above your desire to collect rent in a certain method if this particularly tenant has strong desires to make their payments in a different manner....especially if the lease they signed allowed a different payment method.

Yes it's a huge problem.You should fix this correctly now.Open the walls and put in proper sound reducing insulation.

Quote from @Chris Pontello: Hi Chris,Correct me if I'm wrong as I'm still learning creative financing solutions, but paying them some money would be if I could take over the loan.

I’ve worked with a few tools for property intel, and while no service is 100% accurate, some options have stood out for specific use cases:BatchLeads: They offer a solid skip-tracing tool with good accuracy and detailed reports.

From the public website,The BetterLife Tribe program offers everything you need to achieve real estate success:Monthly Calls with Brandon Turner and top real estate experts, providing you with insider knowledge and strategies.1-on-1 Personalized Coaching to tailor a growth plan specific to your goals and challenges.Access to the reiOS System of Success, the exact operating system Brandon used to scale Open Door Capital to over $1B in assets.World-Class Real Estate Education and Tools that equip you with the skills to dominate any market.A Thriving Network of 1,000+ Active Investors ready to support, inspire, and challenge you on your journey.Seems like a great program like many do in the marketing materials

Additional resources and tools via brokerage.... 

He is correct that a single ADU in a single family zoned area is unlikely to return as much as the hands off cost and is one of many reasons that adding a single ADU in most single family areas is not a good re investment.  

If he kept the house, then your statement would be correct, because there is no immediate taxation of insurance payout.

Remember, most county assessors either have the info somewhat incorrect or their websites will be nearly impossible to figure out correct sq footage, especially for unfinished areas.

Visit RestoreFMB.com for practical resources and tools that can be replicated in other communities to help LA through this process.No one rebuilds alone.