My mom died if a brain aneurysm at 42. her migraines got much worse prior. mine now are too. a both have behcets. could this be hereditary?

Possible: Migraines are indeed hereditary, but that does not mean you have an underlying aneurysm. However, in view of your family history, would suggest a ct-angio just in case, and perhaps kidney ultrasound or abdominal ct looking for polycystic kidney issues, which can be associated with aneurysms. Hopefully this will reassure you.

Probably: Your question is made more complex by your medical history and that of your mom. Behchets syndrome, which can lead to vasculitis involving the arteries of the brain. This could result in bleeding from break down of an artery, similar to how an artery bleeds from a berry aneurysm that ruptures. There appears to be genetic predisposition to susceptibility to behchets syn. And to berry aneurysms.