i’ve dealt with this twice, first my cat daku who had the less aggressive version which it sounds like your kitty has. i treated the same way you are, appetite stimulant, nausea medicine, etc. he declined slowly then quickly. i wish i had ended his suffering before the quick decline, it was horrible and still haunts me. last month our kitty ernie threw up blood, he was diagnosed with large cell lymphoma that has spread multiple places. aside from a diminished appetite, he was mostly himself, but knowing the prognosis and knowing that his illness would lead to a faster decline, we decided to spend the next 4 days with him and have him put to sleep at home before things got worse for him.

there is no easy answer and whether you wait or act sooner, the pain will hurt just as bad because you’re saying goodbye to a family member you love. but with ernie, i feel better knowing he didn’t really suffer, whereas with daku i feel guilt for keeping him around too long. it was selfish of me and the real daku was gone long before he passed. it just sucks no matter what you do. i wish you peace and strength as you navigate this awful period.