Why is my mom's health deteriorating even after undergoing treatment for anaplastic astrocytoma?

Hi doctor,

Four years ago, my mom was diagnosed with an anaplastic astrocytoma in the right parieto-occipital region. She underwent radiotherapy and chemotherapy with Temozolomide, which shrunk the lesion. Over the years her mobility has declined significantly. She can only walk a few steps with support. Her recent magnetic resonance imaging (MRI), which she got last week, showed that her lesion is stable. However, for the past one month, she has been sleeping a lot. Her cognitive function and memory have deteriorated sharply. She has had episodes of being disoriented and is silent mostly, almost dazed. She was in the intensive care unit (ICU) after her last episode of confusion, drowsiness, right hand and leg jerking. The neurologist said she was probably in a postictal state. Yesterday, after being discharged from the hospital, she was very sleepy again, her head slumped, and she took about five minutes to regain consciousness. Today morning she started dazing again. She is on Keppra 2 g, Lamotrigine 150 mg twice daily, Lacosamide 100 mg twice daily, Frisium 10 mg once daily and Clobazam 10 mg twice a day. She had three episodes of seizures in the last year. The neurologist is confused as MRI has shown chemotherapy-induced changes, but still, her condition is not improving. Please help.