The law’s the law.
There are thousands of homes in the same situation, right now, in Dallas/Ft Worth, I’m sure.
http://dallas.craigslist.org/search/rea?query=foreclosure&srchType=A&minAsk=&maxAsk=&bedrooms=
That’s what I say. Are there property taxes related to the property? Those taxes will be his burden.
That’s really stretching the concept of Adverse Possession almost to the breaking point. It was meant to cover things like people walking through your property to get to the beach. If you don’t make any attempt to stop them or to cut-off access, after seven years it is assumed you don’t care and it is considered to be a public thoroughfare.