His sobriety and his further recovery is entirely up to him, as you already know, and if he's truly gained a deep understanding of his addiction and his requirements to maintain sober and continue in his recovery during this period of treatment, then he will know what to do with the wine. That doesn't necessarily mean getting rid of it, although that's one obvious option; the main point is that they are his and they have a connection to his addiction, so that's part of his work, whether or not wine was a part of his substance addiction.
But the real gist of your post concerns the fear of relapse. This is something that requires quite a bit of work on your end, because relapse is something that you have absolutely no control over. I'm not saying that your husband will relapse, nor am I saying that he will not – that's his deal, his side of the street, his story. I am saying that you need to work on your fear of relapse, for your own health, because otherwise it might twist your guts up so much that you'll be feeling that there's a gun pointed at your heart day in and day out. I write this from my own experience.
Your father-in-law sounds like someone who loves his son very much, but unfortunately has no idea how little control he has over the actions of others. When your husband is ready to maintain his sobriety and continue walking a path of recovery, he will do so – let's pray that he's ready now. He made a very direct statement regarding his wine collection, and yet his wishes might be ignored; that is not respectful, even though it would be done in order to "help" him.
One thing that took me quite a while to really comprehend is that NOTHING can stop an addict from consuming substances if he or she wants to do so. And our desire/need to control comes from the fear of this reality.