Firstly, sorry to hear about your problem; it's people like your neighbour that are giving the responsible majority of us a bad name.
Night flying (if by "night" you mean after twilight) is prohibited under part 107 of the FAA regulations unless you have a waiver, and is now prohibited entirely for recreational flights. I'd try a friendly request first, just in case you have better luck than your wife, and be sure to mention Part 107 and waivers.
If that doesn't work, I'd suggest getting some proof of night-flying and the proximity to your windows (e.g. mobile phone video) and take that to your local police along with a copy of a guide to the FAA regs. like
this one for recreational flights and
this one for Part 107 flights. Be sure to point out the bits in the guides about night flying and that he's probably committing a federal offence, and also the potential "peeping tom" angle. If they still won't act, you could escalate to the FAA and/or look into getting a restraining order of some kind, but you'll need to talk to a lawyer on the latter point.
Good luck, and hope you get this resolved soon.