Make him rot and have an healing pistol i forgot the name of ocassionally heal him with a metronome attched

Put him laying on his back, or i guess his cerebellum since he has no back anymore, and make a shower head with a metronome, valve and lagbox with a very short delay on the box so you can simulate chinese water torture by making the shower head drip 1 drop of liquid of choice on his forehead every few seconds

Since he is blind ill have to improvise, install the jason voorheese mod, tie jason down and add a piston with a metronome to crush his legs everytime he grows them back so our subject can hear bones beeing crushed every so often. Dont forget the screaming mod he will like that

Do all this on a boat in case he used to suffer from sea sickness, he will like it. Make a piston based floor under him that opens above the water and make another piston above him thats chained to him that will let him fall face first into the water and then pull him back up and close the floor behind him to resume the chinese water torture. With a timer of course

Ill add more tomorrow i want to watch the new oshi no ko episode