Trying to understand........

My 37 year old brother was diagnosed with a pituitary tumor 6 years ago, and doctors removed his pituitary gland 5 years ago in order to remove the tumor.  He has been on hormone replacement meds and shots since the surgery.  He was recently diagnosed with another tumor on his carotid artery.  Doctor's say it is about 1" and growing.  They don't think they can remove it through his nose as they did with the pituitary tumor because of too much scar tissue, so they are recommending radiation therapy.  My question is:  Will the radiation remove the tumor eventually, what are the risks, and are these types of tumors hereditary?  He has a wife and 6 kids ages 5 to 16.  Are his children at risk of getting these?  Am I or our younger brother at risk?