With mine , I always made sure that I had the borrowing capacity up my sleeve just in case . I'm pretty conservative anyway rather than be fully stretched so I let a couple of other opportunities pass by.
I did worry about it originally as I was keen to do something years back but I eventually realized that stressing over it just wasn't worth it . Once I got my head around it , I put in the bottom drawer and got on with other stuff . There's always other stuff to do !!
Sounds like your neighbour either has plenty of cash ( which means he's wasting it ) or he's not real bright .
Have you considered that if he does get his price you might be able to sell yours to the buyer as well . Funny how these things work out sometimes .
The main thing to remember is that because you have the adjoining property you ultimately have the upper hand .
