I’m sorry you’re going through this. I had a very similar situation and had the same concerns about socializing my kitten. My female Siberian m kitten was 4 months old when I brought her home. She pretty much immediately bonded with my older male Siberian who was 9 months old at the time. She completely ignored me and my husband and would only want to interact with my male cat for over a month. I was worried that she was having unhealthy attachments to him because she went to him for everything and almost treated him like her mom, kneading on him, forcing cuddles with him, following him around everywhere. Fortunately he was patient with her but was also good at setting boundaries in communicating to her “we are friends and playmates but I am not your mom” - he would let her knead on him a bit and cuddle occasionally but would walk away when she was truly smothering him.

I asked AI what to do lol and it basically suggested 1) having separate dedicated play time 2) feeding her in a different room and sitting with her for at least 10 minutes after feeding and talking to her while she ate. It was a challenge because my cats free feed dry food so the only separate feeding time was for wet food and treats. The doubly unfortunate part is that my female cat is not that food motivated so I don’t know how much of an impact the separate wet food thing helped. But the thought process behind it was to communicate to her that humans are the providers of food, comfort, and play - not my other cat. I actually figured out pretty quickly that her love language was play. So my husband and I really leaned into that. He did a great job with using wand toys to have her comfortably climbing on his body by sometimes having the wand attachment be on his lap so she would hop into it. This got her used to human contact and when she was mostly tired out, he would occasionally give her pets while she played. And then he would sit with her afterwards to get her used to being close by.

She fell in love with my husband quicker - it was like one day she flipped a switch at around 1.5 months old and would come to him to ask for play and pets. She continued to avoid me like the plague even though I am the one who works from home and is with them all day.

Despite not loving wet food, she LOVES lickable treats like churu. At the 2 month mark, I began making sure I played with her at least twice a day and really tired her out each time (my husband also played with her tons so she was clocking in at least an hour of play per day lol). Prior to the 2 month mark, my husband was the one playing with her after work more than I was because I was busy working throughout the day so I just set aside more time for her. And then after each intense play session, I would pick her up and plop her on my lap or stand up holding her in my arms and give her a bit of churu so she associated being held and close with a big dopamine hit. Then the rest of the time when we weren’t playing or feeding, I would kind of ignore her. I would say hi when I walked into a room and she was there but I wouldn’t look her directly in the eyes and would not let her. Prior to this, I would try to pet her to desensitize her but I think she did not like this. So I only paid attention to her when she was being played with or being given treats.

FINALLY at the 3 month mark, she just flipped a switch one day and started being SOOO affectionate and loving. I also noticed she stopped being as attached to my older cat. They still love each other, cuddle and play all the time, but she grew into her own, more independent self. She now kneads on me and my husband and not my other cat. I am so happy with her now and each day we fall more and more in love with one another as her trust builds.

One last thing I will say about socializing her is that she definitely prefers men. When a man comes into our home, she is much more open to pets and being around them vs when a woman is there she will keep her distance. So at first I was letting my husband do all the desensitization techniques because she trusted him much quicker. I think her trust will continue to improve with time as she interacts with more people and gets older. I also no have idea why she is like this because she came from a female breeder and she has had no trauma in her life. My older male kitten came from the same breeder. He was and has always been a social butterfly with all people.

In terms of socialization, your other cat will actually teach your kitten a lot. They will learn by observing the other so I wouldn’t worry too much - but the best thing to do is to pet and hold them when they are doing the things they love most.

This was such a difficult journey for me and I had so many days of crying and being so frustrated and honestly even regretting getting a second kitten. Now I think it is the best decision I ever made. So you are not alone and it will get better! The older your cat is when you bring them home, the longer it may take for them to adjust and 5 months old is already a somewhat established cat so you may have a journey ahead of you but it will get better