Husbands back looks like a question mark has pain from his butt dwn his leg. Feels numb cold tingly.?

Sounds like a disc . Causing spasmodic scoliosis due to a herniation leading to sciatica with pain down leg due to disc compressing the nerve leading to neurologic symptoms. Most get better without surgery-10% need surgery. Time, activity modification, medication, guided exercise or physical therapy & epidural steroid injections are options. Weight control, not smoking & regular exercise are preventative measures.