How would you like it if you were in his shoes and your landlord wanted to kick you out because you had health issues and nothing else? 

For seller financing, I think it makes the most sense when thinking about this to try to put yourself into the seller's shoes. 

But, as far as your rights go, you step into the shoes of the owner of the contract you bought. 

Where I live, anyway, the Housing Authority is very approachable, as well as being no-nonsense.So, in your shoes, I'd start with the Housing Authority. 

I think what I'd do in your shoes, is tell the tenant that if they sign a document that says that you will make every effort to re-rent asap, and in order to do that you need access to the unit, but that the tenant agrees that this does not constitute taking possession as far as alleviating them of their duty to pay rent, then you'll get started immediately trying to find a new tenant.  

Think in terms of being in their shoes. 

:)Put yourself in their shoes. 

If in your shoes, I would pay them to coach me on management skills specific to your state and market.

One thing I have seen over the years is the landlord or PM tells the tenant the property has to be paid for and the banks do not care about their situation.You go from a greedy landlord that is rich to being in the tenants shoes just trying to make a payment to get by and pay " the man ".Not the exact words but you are trying to portray that you have no control over the process and what happens next is automatic if they do not pay.

Just my opinion, but if I was in your shoes and I could somehow swing the nicer property, I'd go for that one.