Kinda looks like getting into whizzing contests to see who can high mark the barn wall,, followed by lots of money being spent on lawyers is sop.

(personally I don't like supporting lawyers just to win some whizzing contest on barn walls)

After 7 years Jack Black has the biggest stick, as the dingdong across the road in the last 7 years made not one complaint.

If it were me I would ask the guy what the issues were, explain the legalality of the siituation.  What I would leave him with is the following. "Well as the pipeline has been there for 7 years, it's going to be a real expensive legal battle, Both you and I will wind up spending thousands of dollars on Attorney's, then there's court costs.  And in the end you "might" wind up winning but based on case law and the history of lawsuits of this kind after 7 years there's never been a sucessful suit brought 7 years after the fact.  Now, I don't expect an immediate answer, go ahead and think it over for a few days,,, then let me know if you're willing to spend Thousands of dollars-time- and persue this course of action or,, if you're willing to just let that pipeline remain as is." 

I would also apply the same logic with the letters to the Aunt.

It's fairly clear the guy hasn't a leg to stand on,, and it's absolutely crystal clear he's dumber than a rock.  So, very nicely just lay out his options and give the bonehead a chance to use his 2 or 3 functioning brain cells to figure out what IS actually in his best interest. Once he figures out he will wind up thousands of dollars poorer, and wind up with even more onerous restrictions about Jack Black's pipe, he will leave the pipe alone and stop his whinning.

Right now,, he thinks he's winning cause nobody's calling his bluff,, and he's feeling loud and proud.  Soon as he figures out he's going to be supporting an Lawyer,, and not solving anything he'll wise up!... some anyway...

OR,, you can go ahead whizz in his cherrios,, spend money on supporting lawyers and win  something you were right on in the beginning.

Just boils down to how much money Jack Black is willing to spend to prove he's right.  I'd rather prove I'm right and not have to spend a dime.