So sorry for your loss. We had a cockatiel that flew away, and his mate saw him fly out. She was devastated for 2 days, would not come off the ceiling fan, calling for him all day. Finally she came down, depressed, stayed in the cage for over a month. They always had a mirror in their cage but she never bothered with it, but I sat talking to her, telling her how much we miss him and we know she does too, and sometimes I tapped my finger on the mirror, after a while she noticed it and started kissing it, chirping to it too. These things seem to have helped her get over her depression, and she started coming to me again. I agree too, please don't abandon the cat. Find him a home. Your bird will come around if you pay extra attention to him, but keep in mind if you get another cockatiel they may not get along, but I have found most of the time they do as they are pretty mellow. If you do get another one, might be a good idea to get a separate cage for him/her. Then if they want to be together or apart you will know, and neither one of the birds will be upset.Even if they do get along good sometimes they want their own space. I wish you well, Pat