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

My son is now 24. I do think that I can get answers from his doctors, unfortunately I don't think his doctors chemo oncologist and neurologist often agree.
In September 2010 our son had a series of serious seizures (try saying that 10 times real fast, LOL) The neurologist told us that his cancer was increased from astrocytoma grade 2 to GBM--of course this floored me, but I trusted the dr. information and expertise. But then after thinking about it I wondered how he could make this diagnosis without another biopsy.
In September 2010 his chemo oncologist somehow did not get the information that he was hospitalized for these seizures. When we went for his oncology appt. we told the dr. then. He looked at the MRI from that visit and told us he felt like the seizures and the look of the MRI showed possible shadows as a result of the radiation.
Now we are just confused---I don't like to talk about Micahs health in front of him---I don't like talking about it like he is not in the room.
I think what I need to do is get the first initial diagnosis---we were told astrocytoma but never given a grade, but I have heard neuro. mention astrocytoma grade 2.