Hi! My fiance and I are mattress shopping for the best bed for his back. He’s got a torn rotator cuff (from a construction accident)PLUS a lower back with 3 disks over 50% degenerated (from a car accident). Is there a certain kind of mattress you would recommend? Are those sleep number beds all they’re cracked up to be? What about the posture-pedic? Right now he’s sleeping on an old mattress and he hasn’t had a restful night’s sleep for about 5 months!