Put yourself in Aldo's shoes for a few minutes, then answer.
For the past 13 years. I have always maintained the land directly behind my property. Is there a law stating I can claim it as my own?
It is impossible for him to take ownership (Maybe a sneaky, underhanded "Quick Claim Deed" with an ad in the paper and all the legalities) of the property in any legal way, even if it is 50 Years, so in all respect, my suggestion would be the most beneficial and least instigating, because it is the SOLUTION, without breaking any laws.
The questioner did not ask to build a garage on that strip of land. THEN, therefore that would be a problem, and a whole new question..

