My cat is depressed 5 months after his companion died. Is he sick?

These kittens are very young and the fact that a sibling passed away is very concerning. They need to see a vet to check for different viral and bacterial infections that they could be suffering from which may have been the cause of death with the one that passed. They are pretty young to be showing signs of depression.

Yes, this is concerning. First I'd have him checked by a vet to make sure Phoenix isn't sick. If he's healthy, then I would consider getting him a companion. I'm very sorry for your loss of Blizzard.

I suggest you try some Feliway diffusers to see if it will help him. Give it a couple months to see if it helps. The diffusers must be changed every 30 days and you need to get enough diffusers to cover the square footage of the house. Also, some environmental enrichment would be a good idea. ( https://www.feliway.com/uk/Products/FELIWAY-CLASSIC-Diffuser ) ( thedrakecenter.com/materials/environmental-enrichment-indoor-cats ) ( https://www.youtube.com/watch?v=AejmrLa_Cs4 )

Thank you for using Petco Pet Education Center, formerly Petcoach. I'm sorry for the loss of your cat, and it sounds like Brostom is taking it pretty hard. Our pets experience grief and loss, and just like people, it takes them a variable amount of time to deal with that loss. If Brostom was very close with the other cat, he might benefit from having another cat in the home to keep him company. If you decide to pursue this, I recommend a slow introduction and keeping the new cat in a separate room for a few days where they can smell each other under the door. If this increases Brostom's agitation, then it might not work, but I think it would be worth trying. I hope this helps.

There are calming supplements and diets which can be very helpful, as well as pheromone and comfort zone diffusers which can help cats adapt to such situations. A full health check and possibly blood panel should be considered to rule out medical causes especially if there is any weight loss or altered thirst

Hello. I am so sorry for the loss of Chicken's brother. If these are recent pictures of Chicken, then he still looks quite robust & healthy. He may very well be missing his brother & this could be causing him some stress. Loss of appetite & sleeping more are certainly signs of depression in people, so why not cats. As long as he is still eating & using the litter box normally, he looks like he will be fine until next Friday. I know you are worried, but he looks OK for now. Give him lots of hugs ( no kisses ). Thanks for using Petco Pet Education Center, formerly Petcoach.

While loss/grief can certainly cause behavioral changes in cats, losing weight, not eating and urinating everywhere make me worry there is an underlying health condition such as a urinary infection that is causing him distress. Not being neutered can also lead to marking behavior/stress if there is a female in heat nearby. It is a good idea to have a thorough exam done along with bloodwork, X-rays and urine tests potentially to determine if there is any health issue. If he checks out healthy, spending more time together may help him to relax some, as well as using a pheromone diffuser such as Feliway to help with the marking behavior/stress. If you think he'd benefit from a friend, gradually introducing a new cat may help as well, but can also be stressful.