car accident , miscarriage

A friend got car accident on the way to see her OB doctor. She was in two months pregnancy. Somebody hit her from behind and his insurance called to accept the responsibility. She was miscarried, she was bleeding one day before the car accident, that was why she made the emergnecy appointment and went to see OB. OB doctor said her miscarige was not related to the car accident. She bleed more after the accident and feel much cramping, etc. Now for sure she was miscarried already.

Old cat? What do you think? Should my friend file personal injury? How positive could she get some compensation?