Will having resection for grade 2 astrocytoma in left frontal lobe affect personality, emotional faculties, learning ability or cause regression of intelligence?

My son had 2 resections to remove grade 2 astrocytoma in 2010. After second resection he began having seizures. Two questions, could these 2 resections affect his personality, emotional faculties and cause him to act more immaturely than before the surgeries? Also, are the seizures considered epilepsy...or reactive to resections.
He had radiation shortly after second surgery, along with chemotherapy. He continues he chemotherapy treatments as of this month.
I guess I also have a third question....can a doctor upgrade to GBM without a further biposy, just based on seizure activity?