Unusual behavior with glioblastoma

I have posted before. Our 50-year-old son has inoperable grade 4 glioblastoma. He has completed radiation and chemo and is currently on rest from both. We’ve noticed significant disintegration. He is getting no PT OT and now he does not speak. He only get out of bed to eat and then goes right back. He does not wish to talk to any of his siblings or his parents. Beyond that, he is seemingly just outright ungrateful, never a please or thank you for anything. It’s very hard to tell whether this is a sign of a tumor growing despite treatment or if he just doesn’t want to be bothered by anyone or anything. It’s all a bit confusing. He seemingly has lost his fight or Will to live. Has anyone had similar experiences? While we are not giving up hope, he seems to be knocking at death’s doorstep. We will get results from his post radiation MRI on 10/12.