Strange times, Reading your post brought back memories of when my husband passed this past summer.
He had MM and MF, along with liver cancer and the cancer spread to his spinal cord, making him paralyzed the last few months of his life. His BP was up at an alarming rate, and his dr and i phoned/texed each other with his vitals all day for the last week of his life. The Friday before he passed, his bp was so high, the dr told me to be prepared he was going to pass that day. I told him that he was going to wait till Sunday and the dr asked me how i knew; i didn't, i just felt it.
Our kids and their spouses moved in that Friday, and we all stayed close to my husband. I slept in a chair next to him (instead of sleeping on the floor next to him) holding his hand. He was having numerous heart attacks that Friday and Saturday. I kept him as comfortable with the meds you mentioned, along with his morphine. Sunday, he started the foaming at the mouth, just like you describe. Scared the daylights out of our sons and their wives, but having been thru death with my parents, i knew what to expect.
I told the kids to keep talking to him, and they did not know what to say, but i told them to talk about anything and everything. They tried to talk, but kept breaking down. I sat and talked to my husband about things we did, our dogs, the grandbabies (3), and i never said goodbye. After he passed holding my hand with his body on an angle facing me, i told him i would see him later. Don't believe in goodbyes as i know i will see him later.
He did pass that Sunday morning, just as i had told the dr. The dr called me as he was immediately notified by hospice, and asked me how i knew. I told him that him passing was his final gift to me. No more care giving, no more special meals, no more injections/chemo, drugs; he was relieving me of all my nursing duties. It was my birthday.
He never really struggled, I think the kids struggled more watching the process (they are 30 and 35). He passed peacefully, but the oddest thing was, when i was holding his hand, i felt the cold rush thru his hand and arm, just before he passed.
My thoughts are with you on this whole journey. Mine is still as fresh in my mind as if it were yesterday.
sue