Tingling in limbs. Due to disc slipping?

Hello, my father has been experiencing continuous tingling in the limbs and on face since last 2 months. He had limbo-sacral slip disc problem which was cured by physiotherapy by Dr. Sarangpani, Pune. It was advised to keep the exercises going since then and he couldn't do it for couple of months in between. The problem arose again with tingling in the hands, legs and face which makes him not feel them. There is no external pain just numbness. Sometimes the veins/nerves pain a lot from inside. He is not able to get sound sleep because of the pain from inside and numbness on the outside when rested. Can you please advise if it's a neurological problem or because of compression of veins due to disc slipping?