My Cat Is Feral Should I Let Him Go?

I have two cats (American shorthair) Popeye and grandpa. I've had them since they were young get they're vastly different. Popeye loves me and my boyfriend he loves affection and attention his brother does not. They live each other but grandpa is not a house cat I believe he wants to leave he often tries to escape. Feral cats will leave no matter how much you try to prevent it, should I let him go? I don't want pops to become depressed, I just truly feel grandpa does not feel free or safe here.
My Cat Is Feral Should I Let Him Go?
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