We had exact same problem some years ago in another house, moved out after 6 months, just hated being in my home with the noise pollution from next door.
I could even hear him having a pee in his downstairs toilet.....Nice.
Had a chat to the guy, about the thin walls etc, all very nicely done, next thing, volume on TV is RIGHT up.
At that time I had a Marshall amp for a bass guitar 200watts output, Plumbed it into stereo and blasted Aerosmith through the adjoining wall over a weekend when we went away.
That sorted it out...... but it was never the same, always listening out for noise next door, I was never at ease living there after that.
Good luck, but it will eventually drive you outta your home unless you are very very easy going, but, somehow I don't think you are.