Hmmm..........I don't know that he would find it comforting. He may feel somewhat good that after the shaky past, there is some experience that he can convey that might be helpful. Your son's reaction may be somewhat.........."I am not like you".
This may be a result of the inner denial that there is a similar problem. I have discussed my past with my son to an extent. I want him to know that if there are ever issues, that I am available. Course he says now, as did his sister, that he will never drink, never take the chance. I really can't say about your ex, but I know I would be comfortable helping my son if he ever needed it, but needing it would be anything but comforting for me. I hope he does not have to experience what I did.