Is the only option to spend a bunch of time building a wooden frame?
Does anyone just sell an easy to assemble frame kit?
Would it be possible to just lay down some thick yoga mats to level everything out? (Like this one: https://www.amazon.com/dp/B00FO9U46W/ref=cm_sw_r_api_i_N6X2DRXA6CW02425V0NB_0 )
I bought a mat similar to this one (mine is only 1cm thick) to exercise on my mother's suggestion, it is actually comfortable to use as it is thick.
If you will be flipping in one location (vs. flipping on the go, while walking or other travel), you might get less breakage by investing in a thick yoga mat to lay out beneath the flipping "zone". A yoga mat should do a great job of absorbing a lot of impact force.
I use a 1/2 inch exercise mat. I think I got mine from my local TJ maxx or Marshall's for $15-20. There's this one on amazon. I highly prefer thicker mats for the extra cushioning
Yeah just go buy one of those mats for a few bucks, or buy something like this and cut some squares out of it, that way you can be sure they work well and you don't need to bother him again (unless you've seen his speakers then go off what you've seen). Apologize (even if you don't mean it lol) but go down there with it. Just emphasize how you understand this is an inconvenience but that him doing this just one time will make for hours worth of more pleasant nights for you.
Also it may help to let him know you have a sensory condition that makes the vibrations torturous. Seriously a lot of people that isn't even remotely close to a possibility in their head. You kind of have to kindly educate them to be more empathetic towards you. It's not an insult to you, it's just human nature. But he'll be way more likely to do it if you buy it for him because it will not only make it so he doesn't have to put forth as much effort but it also shows him you're willing to put some money behind it.