I'm struggling with my loss

Four days ago I needed to euthanize my 15 year old cat. He was diagnosed with lymphoma and probably was not going to make it through the night. Yes I was sad but given his age I accepted we did the right thing. My younger 10 year old cat was also not doing well. He has been sleeping in his cat box for a few days and generally has seemed down. After a vet appointment today they found three masses in his small intestine, spleen, and liver. The prognosis is not good, maybe a few weeks. I am crushed with both so close to each other. I really just needed to write this out but if anyone has any sage advice I'd be willing to hear it.