Legs are weak, can't walk. Should we do.

If you think it's a sudden thing that he cannot walk please show a physician If it's due to general weakness give him a little time and​ consult a physician

Quadriceps exercises in gradually process must for him Cycling u can also for strength

Quadriceps strengthening exercises- Quad Clenches: Lie flat on your back or sit upright on a chair with leg kept horizontally on another surface. Now, tighten the muscle on the front of the thigh by pushing your knee down. You should feel your thigh muscles clench, Hold for 3 secs. Repeat 10 times twice a day. Short Arcs: Lie flat on your back or sit upright with your leg placed horizontally on a flat surface like a chair or bed. Place a rolled up towel under the knee. Pull your toes towards you and clench you thigh muscles. Slowly lift your foot up off the bed until your knee is straight (keep your knee resting on the towel). Hold for 3 secs and slowly lower them on the chair. Repeat 10 times twice a day. Straight Leg Raise: Lie flat on your back. One leg and knee will be straight and other leg should be bent. Pull your toes towards you and tighten/clench the muscle on the front of the thigh, locking your knee straight. Lift your foot up in the air, about 6 inches off the bed. Hold for 3 secs and slowly lower the leg. The knee must remain straight the whole time you are doing this exercise.

He could be suffering from low Vitamin D3, calcium or Vitamin B12. Get these checked first and take the necessary supplements from your family physician. Meanwhile, ask him to move around in the house and not take bed rest. Once he is on the bed, his muscles will get more weak. So ask him to move around. Start with 4-5 min slow walk in the house and gradually keep increasing the time duration. Ask him to sit on a chair and extend his knees, lift his leg up from the hip (just general movements of the legs). This will help in maintaining his mobility. I also advice seeing a physiotherapist, as it will assist and motivate him. Hope this helps. Kind Regards, Dr. Kshama Dhawan, Shah Polyclinic.