My Husband Has A Grade Level 2 Astrocytoma ( Very

My husband has a grade level 2 astrocytoma ( very small) in the left parietal lobe. He had 33 radiation treatments ending 9 months ago. His last MRI showed diffuse atrophic changes of brain parenchyma. There are conglomerate regions of high signal intensity in peri ventricular & sub cortical white matter of the brain. What does mean for my husband's future cognitive abilities especially in the areas of receptive and expressive language? Is this condition progressive? Thank you vey much for whatever information a you can provide.