I’m sorry for your loss. Well then, if you know it’s not a physical problem then I would suggest any or all of the following;
1) Play with him a lot right before bed to tire him out.
2) Feed him right before you go to bed after 1)
3) Use ear plugs and a hepa filter or some other form of "white noise" after 1) and 2)
Hugs,—CatNipped