Sudden onset of extreme brain fog / confusion

Hello all, 

I'm wondering whether any of you have some experience of this you could share because I'm really struggling to handle this new symptom. I've read back through a lot of posts, but couldn't see any about this, so starting a new one. 

My husband was diagnosed with pancreatic neuroendocrine cancer which had already spread to his liver in January this year, he's had two types of chemotherapy which didn't work and we've just been told he can have one last-ditch third line treatment which we're considering. Alongside the oncologist, he's on palliative care for pain management, and we've been told that without treatment, his life expectancy is 3-6 months. He's only 51, I'm 46. We'll have been married for 18 years if we make it as far as December. 

He's lost a lot of weight, is definitely weaker than he used to be but up until recently, you honestly wouldn't know he was as sick as he is. However, things have suddenly got worse over the last week and a bit. The chemo 'brain fog' has suddenly tipped into really bad confusion and memory loss - his palliative care team are investigating whether it's related to low blood glucose levels (he's type 3C diabetic thanks to the pancreatic cancer), a side-effect of the morphine and amytriptilne he's taking, or something 'more sinister' (their words).  

This has been such a horrible blow for me. I've been told I'm coping 'amazingly well' with everything that we've faced since January - the chemo, the side effects, his high pain levels, the knowledge from day one that it's terminal - but that was because we were going through it together, and over the last week and a bit, he really hasn't been himself and it feels like I've already lost the person I love, but I'm still here caring for him. It's really, really bad - he's lost all sense of time passing and it can take an hour for him to get dressed, he finds it hard to follow a conversation, and answering questions takes forever as the words don't come easily to him: he gets frustrated when I try to prompt him. It's such a contrast from my loving, funny, quick-witted and caring husband, and it feels too soon to say goodbye to that. 

I'm scared he's going to be too foggy and unwell for the third-line treatment to go ahead, I'm scared that this is the start of him declining towards the end, I'm scared that the one thing that's kept me going through this, the ability to say "It's going to get terrible, but not today" is about to run out, and I don't know how I'll cope when it does. But most of all, and the reason I'm writing, is that if there's anything we could do to ease this for him, something we've got thought of, questions we should be asking the medical team, I want to know because I hate feeling this helpless. 

Have any of you been through something similar?