The problems you stated, point towards a spinal cord injury
that occured during the accident. Spinal Cord is the nerves in the bach that carry signal from the brain to the legs and back. Something like electric wires.
When these nerves get cut/damaged, their is no transmission of signal. So there is no feeling in legs and no feeling of urine.
With such severe injuries, there is no such medicines or surgery that can repair the cord and bring complete recovery of function.
What is feasible is rehabilitation
. Training in the form of learning self transfers from bed to wheelchair, self intermittent catheterization of the bladder etc.
There is extensive research going on with the use of stem cells in such patients, with a few claiming minor improvements. But this is still in the research phase.