Maybe move his crate near a downstairs couch or get an air mattress so you can sleep near him for the next 2 months? Or start working now on making him more comfortable being in there at night so that it's not as big of a deal post-op. I don't know exactly how you would go about doing that. maybe back to basic crate training but with the added routine of turning the lights off and going upstairs.
If you have two different crates one upstairs that he always sleeps in and a different one downstairs, it may help to swap and bring his usual sleeping crate downstairs. I bet there would be a difference in the scent to him and knows the other one is where he is meant to sleep.

I don't have first hand experience with TPLO surgery... My dog has this injury but he is old and I decided against the surgery (he is getting double leg braces next week!) I can only really offer advice for helping the constant rest be more enjoyable for him: mental exercise.

• lots of brushing and petting/ massages.
  
• frozen treats in kongs and new puzzle toys
  
• reinforcing/ training new tricks that can be done lying down (pick an object with paw, touch with nose, speak, on your side, etc)

I'm also planning to try out hydrotherapy and I have read it can help after surgery.

Good luck for the surgery and I hope he starts to recover well!