My father has had severe lower back pain on both sides of spine, then started with tingling in feet and lower leg.  Very rapidly he has deteriorated to the extent that his legs are numb and he is virtually unable to walk, he drags his left leg and lurches from furniture to furniture to walk to the toilet, he is virtually bedriden.
HI Erica, Your dad be having degenerative changes in vertebral bone with disc prolapse leading to compression of nerve root causing pain and numbness and weakness. He requires urgent decompression, consult euro surgeon. Take care