my son has accused and cancelled me

Dear Nicholeen –
I have just been through three weeks of the worst pain I have ever felt.
Some time back, I wrote to you about my 24 year old son who was distancing more and more from me and would not tell me why. Just to remind you, he had a psychotic episode about 4 years ago when he remembered being sexually abused by a teacher. I supported him through that and he recovered enough to feel that he could move out, start a job and become self-supporting. Until the point that he moved out, I would have said that he and I had the closest relationship of any of my sons (I have three sons and one daughter.). Until then, I felt that our relationship was very secure, that he knew he could count on me. So I was very bewildered when he started distancing more and more. You suggested that I send him a letter of apology for all the mistakes I had made and I did that. He did not respond but that was ok. Then – boom – three weeks ago he wrote me that he remembers that I sexually abused him when he was very little and that this is why he's furious with me. When I said that I have no memories of ever, ever molesting him and that it was not something that had even once crossed my mind with him or any other person, he said that I must be suppressing the memories of what I did. When I asked, he refused to give me any details about what I did to him, or to go to a third party of his choice to work this out together. He told me that if I did not remember it, it was my problem, and I must "come to terms" with what I did.
He is, thank goodness, connected with his siblings and they speak to him weekly, but he will never speak about me (or his dad, from whom he has been completely cut off for three years). But my children tell me that, as far as they can ascertain from a whats app call, he seems to be doing better now than in the past. When he was still psychotic and trying to figure out exactly what happened to him, he did ask me if I had ever sexually abused him, and I told him no. I wonder if that doubt he felt just never left his brain and then got magnified through therapy or just on its own. Part of me wishes I could just tell him I did it, if it would help our relationship – even though I know that would not ultimately be helpful. I pray every day that G-d should reveal it to me if I did do such a thing, and that if I didn't, He should help my son know the truth. I try to have hope for the future, but I am devastated. Any words of comfort/advice greatly appreciated.