Medical Negligence Claims.

Does anyone know anything about medical negligence?

My family is at the beginning of a possible negligence case.  My brother was taken by ambulance because he was taken very ill with a headache and vomiting.  He was kepts in overnight  and diagnosed with migraine.   Even though it was obvious he was very ill,  he was send home.  I even argued with the staff he wasn't fit to go.  However I was told he has been cleared to leave. So he has to leave.
He collapsed once home and we had to call another ambulance.   This time he was taken to a different hospital.  A ct scan found he had suffered a stroke.   Result is he has lost most if his eyesight.
I made a complaint and have just received the completed investigation report.  It clearly states mistakes were made and guidlines were not followed.   I am awaiting direction from a solicitor as to what can be done.  Has anyone any experience with things like this?
Any advice you could give would be appreciated.     Thank you.