You must also make reasonable accommodations for them.

The property is not located on a hill and it is certainly not in an area that would accommodate a high-rise so that makes me wonder. 

We rehabbed the bottom floor to accommodate my inlaws for about a year.

If you want to find out more about a DST, ask your 1031 Exchange Accommodator - also called QI (qualified intermediary) for a referral. 

So the answer is for you to offer him a contract allowing him an extended closing to accommodate his 1031. 

My take:- I feel we've been very accommodating with our offer and treatment of all complaints considering tenants caused these issues due to the dryer lint trap in November.

Keep looking around if you go that route, or as your 1031 exchange accommodator for suggestions.

We don't have kids and I will be as flexible as I can be to accommodate what you need.I'm happy to do whatever you believe would be most helpful, wether that's actually doing some of the rehab work (I'm handy, and can also learn quickly if it's something I haven't done previously), or if you need me to follow up on leads, or walk a property that you can't get to.

CON: It sort of cuts into cash flow unless you raise rents to accommodate high usage.

While I do not know the local fire code in Baltimore, here If the building does not have a secondary exit for both units (regulations differ a little depending on whether either entrance/exit is shared vs independent), they would not be legal accommodations.