I’m so sorry 💔 what’s his name and how old is he? did they say what type of cancer ? How’s his appetite ? Years back, my previous dog, Peanut had spleen cancer. His indicator was seizure too. He collapsed once a week, a night of drips at the hosp and the rest of the week a happy boy. We did all we could and were fortunate to have him for many weeks after he was diagnosed. It got harder towards the later stages. I remember my dad would stay on to feed him by hands. But he was a happy boy while he was with us. He was loved. I hope this little bit of information might be of some use to you. My heart breaks for you. I’m so very sorry.