I have studied your case history.
After so many years of injury
and wrist drop
you need surgical tendon transfer for correcting .Nerve
transfer may not work now and physiotherapy
has very less role now.
Some ayurvedic treatment can be suggested with guarded prognosis.
For further details you can directly contact on my profile
Hope this answers your query. If you have additional questions or follow up queries then please do not hesitate in writing to us. I will be happy to answer your queries.
Wishing you good health.