toe pain

My boyfriend has severe toe pain on the left foot, he doesn’t have an ingrown toe nail.
He also has left legpain, and numbness, numbness in whole left foot and toe, and L leg.
What is causing it?
All the doctors he’s been to don’t know.
He has had it for 6 months.
And he has never had any accident.
He is 50 yrs old. Any free advice?