At least where I am, if a tenant becomes disabled after they sign the lease, you are not required to make any modifications to the home. 

With modifications, all our rents have been paid. 

To answer your other questions, you would be able to charge more for the additional space, but I would think that would be negotiated when you make the modification allowing them to convert the drive through space. 

But consult an attorney steeped in private money law.2) this state is HIGHLY regulated so you need to know what you can and cannot do.3) CA recently (2022) had case law against loans that went into default, were worked out with the lender and then default interest was discharged (subject to usury rates) because the loan modification wasn't worked out through the real estate broker who originally supported to loan origination.Bottom line, make sure you explore your legal rights and considerations before lending in this state.

Only cons I have with that is, if the owner would allow me to make some modifications in the house, which is something I wont have to worry if I buy a house.

I used one piece in my arsenal with hardly any modifications for ten years.  

Sometimes, a simple modification can make a big difference.

I recently got a loan modification (5 months ago) fix for 40 years.

The bank is offering 2 options for modification.

I did a loan modification a year later on the 2nd loan.