We bought the home in 2021 with the intention to clear the lot so my grandparents could build an ADA accessible home.

First one was that we might not be ADA compliant, and wouldn't it be a shame if someone were to sue because of that?

Does the Americans with Disabilities Act (ADA) require any modifications to existing structure to make it accessable. 

I’m a little clueless on what needs to be done to comply with ADA in the process of the renovation.

Sadly there is a similar thing occurring in Eastern Washington with a scumbag and his buddy lawyer that drive around to businesses that they never even go to and Sue over ADA discrimination if doors on old buildings are too small or there isn't a ramp etc.

No but there are protected classes that cannot get the shots and it violates ADA law in those cases to discriminate.  

I live in Argyle, TX, which is an exurb on the NW side of the DFW area.I am currently listening to BP podcasts, reading David Greene's BRRRR book, and looking at markets where I have existing connections (Little Rock, AR, Ada, OK, and Natchitoches, LA).

I have a tenant in a mobile home that broke her leg ( not on my property) and is at a rehab facility. The facility called and demanded I install a handicap ramp and rails for her. My contractor says this will cost $80...

Please reference HUD Guidance Memo 2013-01.Also, as someone is bound to make the mistake in this thread and quote the ADA, Americans with Disabities Act....that is a law that governs public accommodations, (things like hotels, restraunts, airports)....the ADA has zero to do with residential real estate.

I believe all states have provisions for terminating a residential lease, examples include (but not limited to) a tenant called to active military duty or change in orders, the death of a tenant (releasing the estate) or of a co-tenant, medical conditions requiring special care or residential amenities, another situation could include ADA compliance after a life changing event.