Let me give you some background before I get to my current situation:

In May of 2023, I took in two approximately 6 week old kittens. They were born to a feral mom, so both were unsocialized. One came around very quickly, and was adopted out once he was fully vetted. But Pippen remained VERY skittish. Full disclosure, I did not have much experience socializing at that time. However, with some time and the help of another foster,  he finally got to the point where he'd hang out with me, etc.

Then came Neuter Day.

Pippen went to a spay/neuter clinic when he was about 4 months. And frankly, SOMETHING happened that day. I'm not saying it's the clinic's fault or that somethinf was intentionally done. But I did not get the "same" cat back that afternoon. I didn't realize there was an issue, so when I got home I let him out of the carrier, and he has never let me willingly touch him since.

It's been three years. I know. Go ahead and judge me. I judge myself every damn day. I live with some significant guilt over "failing" Pippen. He's loved. He lives indoors. He adores my other cats. But he's just a peg or two away from feral, for the most part. He will come out and be visible, etc, when I'm home, but if I stand up or move towards him, he takes off. He will accept treats from my hand.

Now we come today:

I'm taking a break from fostering kittens, because my own senior cat is on hospice. So I got the bright idea to shut Pippen in the foster room and at least TRY to work with him. I owe it to him, because I know a very sweet good boy is in there.

I corralled him last night, and obviously, he's pretty upsetti spaghetti. He's crying a lot. I haven't seen him actually eat food like a meal, but he did take some high value treats from me this morning. I know it will take time and patience; I'm not in a rush. And I accept that this may not have the result I want. 

My question is: if he continues to not actually eat (as in life sustaining eating, not just treats), how long can I safely keep trying before I acknowledge this isn't gonna happen? I know it isn't like weeks, but how many days are we talking? I did order some super high value treat food by the same company that makes his "crack treats," and he is usually very food motivated.

Again, I know I completely failed by not addressing this sooner. There's more to that story than I'm comfortable sharing. But it is what it is now, and like I said, I owe it to him to try and get him to at least not fear ME completely. And even if this doesn't work, \*he will have a home and be loved for the rest of his life\*

Besides my question, any tips or tricks you might have regarding socialing an adult cat are MUCH apparciated.

Pic of my little scaredy guy for tax. I'm letting my other cats in and out of the room, so he's not alone. Pippen is the orange and white guy, and Ziggy is his helpful baby brother.

When to throw on the towel on socializing an adult cat?