My son had a brainstem CM resected 7 years ago. There was no doubt it needed to be removed, and I don't regret the decision to have it done. That said, be sure you ask your NS what the surgical path will be and what s/he considers a good outcome of the surgery to look like. Ask what sort of rehab will likely be required, who will the therapists be (maybe you already have some from your previous bleeds), and if you can, talk to them and ask them what rehab will look like and what a poor, average, and good outcome looks like at one month, three months, six month, etc. Your surgeon will have a different definition of success, and you want to be realistic in what recovery will look like so you don't get discouraged in the long slog. Also, be prepared for personality changes due to the surgical path. Brain surgery creates a new injury in hopes of mitigating an existing one, so you can't be sure what will change.
My son's story is sprinkled throughout these forums if you are curious.
My son is doing well today, but sometimes it is still so hard!
16 year old son with brainstem CM resected in March 2010, CM at C2-C3,
CCM2 mutation; DH, MIL, & BIL with multiples in brain and spine