I'm sorry that you are going through this and hope that you don't have to alone. We had to endure a similar situation with both my father-in-law and my brother-in-law within two consecutive years. The former wasn't able to speak clearly and the latter not able to speak at all after one life changing moment. My sis-in-law had to go through the ordeal with my brother-in-law alone since he left home and stayed with her for some time to resettle. But she spoke to him as I spoke to my father-in-law, believing that they could hear and understand even if they couldn't reply. Remembering "faith comes by hearing,' I spoke the gospel to my father=in=law, and he appeared to be listening because when I finished, he said, "I feel better." But, up to that point, his speech was incoherent, mumbled and slurred. I couldn't sleep one night and thought to go in just to sit with him. I slipped in and turned on a turner classic movie on near silent and when he stirred and noticed me there and I turned to look at him and he, sternly, asked me, "why?" (he didn't like anyone to fuss and worry over him) so I simply said, "because I love you."
Well, that started what an eavesdropper might've heard as gibberish but, I understood, he quickly replied, "I love you too...but my back is weak, and my knees have been giving me trouble for over 20 years, and my feet..." so I stopped him and said, "I know... but, could you just wait until after Father's Day?....I can't let go on Father's Day.." and he let an exasperated sigh and said, "Okay" and laid his head back into his pillow but said nothing more.
What had led up to that, and why I found it impossible to sleep that night, is that it had happened earlier that he had been trying to tell his sons gathered around him to remove the iv drips and pointing at the mechanism they were attached too. And everyone knowing him, knew he hated the thought of being a burden to any of us no matter what we thought of it. And we miss him so very much.
So, when I noticed the lesion on my mom's person when she leaned over her garden that same summer, and she tried to tell me she wasn't going to bother having anyone look into it when I inquired about it, I said, "oh no, not this time, not now, not when I just lost so...." she knew what a great loss I meant, her having known him, so, for once, she obeyed me, and I took her immediately to someone that sent by ambulance to the cancer treatment center where she began what stretched out as a five-year regime of treatment that culminated with an "attempted" continuation of 'preventive' care at which time I offered my "okay" that she discontinue if she felt it was hurting her more than helping(I realized she wouldn't have quit them, and wouldn't have asked if she could even had she wanted to except that I had given my uncoerced consent). And she, as in the beginning, immediately discontinued the treatments. She still notes to me the debilitating effects from them, but she's still with me and I check in on her, and dad, who is going through many challenges of his own, regularly. But I don't think I'll ever be able to "prepare" myself for the inevitable that we all have to endure sooner or later.
My oldest brother-in-law told us, that evening of Father's Day coming up on 10 years ago, that we should go home and get some rest and he would remain with him, and so we went home. And not being able to sleep, about the moment I breathed out a prayer for comfort to let go, two hours after midnight, his first-born son called to let us know that he had gone to his rest.
Especially at a time that only reveals all of our helplessness, I hope, somehow, this helps, somehow, in this difficult time to endure.