15 year old cat seemed to have breathing problems suddenly -xray showed chest congestion and some fluid in lungs and an irregular heartbeat. His si ter died 2 months ago and he seemed fine but then would go in the cellar and lie down where it was cool and slept there perhaps her scent. Then came upstairs after a couple weeks and would sit on the dining room table with mom. He would just lie and stare at mom but seemed very happy as she is ill.. I'd play with him comb him he seemed to snap out whatever he was in... Made him a bed of magazines on the floor he seemed to enjoy the coolness. I then put a nice white sheet there he loved it and started sleeping there but past couple weeks stayed there more not on table as much but enjoyed drinking water out of a glass more than usual. He never drank like that when his sister was alive . Past couple days I was brushing him which i did every day and he really began to like it and became extremely friendly, i thought great. Noticed a few days ago he got a bit snippy which he had never done before. said maybe a bad day. Then I saw he was not eating much the past couple days..Went back in morning to open drapes heard a cat meow and there was moms cat on the window sill moaning cry and having trouble breathing looking for air. I could not believe my eyes. Went to vet and bad news.. Had to make very tuff decision as cat just lied in his carrier tired and not breathing to well. I was given options but it was no cure just prolong a week or so. Lasix.ultra sound, needle in chest.... Vet seemed to think it was a bit late for all of that... I said to someone that once his sister died I'll bet he'd be gone in 6 months. It has happened to two sets of cats I had and now moms cats. He seemed fine when his sister was alive but obviously went downhill and Hid it very well. Basically heart failure. I wonder if he died of a broken heart. He hid everything so well I am still in shock. Has anyone out there seen this in other cats.......