My Dad aged 47 was diagonosed with a grade 2 astrocytoma in 2008. He has had radiotherapy and chemotherapy that made little improvement and in May 2019 the tumour changed to a high grade glioblastoma with a prognosis of around 3-6 months. 

In the last week he has even falling losing movement on his left side meaning he is now in a wheelchair or in bed, suffering from severe headaches, sleeping a lot and he appears to be quite agitated and difficult in his personality. I have also noticed the movement in his eyes have changed. Doctors have made suggestions that his prognosis may have shortened recently. He will not be having anymore treatment apart from being on a course of steroids to keep him comfortable, along with morphine, seizure tablets and some physio. 

My question really is, what signs am I really looking for to suggest his end of life is near? I just want to keep him as comfortable and happy as possible during this time. 

Thanks in adavance.