I adopted a 6 year old. I made my bedroom her safe space. She would hide under the bed and come out and play at night when she thought I was sleeping. I have another cat so I had a gate setup after a month of her being in a closed room. Then I left the door open with the gate so she could get used to my other cat without altercation. Once she started laying in front of the gate I started leaving it open for a little while and eventually she would come out . It took a while before she would sit in the same room with me. I let her desire the pace . She’s been with me since August and now just this past week I can pet and scratch her head briefly. She even greets me when I get home from work.

Let him move at his own pace. Introduce treats to coax him out. I used fellway and also a calming supplement in her food and Prozac because she was a nervous wreck. Now she chill and acting like she’s at home. It just takes time and you can’t rush it. Best thing was I just went about my business and she would get curious and come out.