Congratulations to your son-in-law who managed to change his bad habits!
I know you are far more educated than me on this subject, but as far as I have understood it, the liver is THE organ in our body that has the ability to recover after most any kind of abuse.
His six years with no alcohol must also have done a lot to his liver! (Beside with such a caring mother-in-law)
As he is now on Liver Cleansing his liver will also be able to obtain more of the good stuff he is consuming.
I don't think you should worry to much about it, if problems concerning bad livers, doesn't run in his family.
Keep up your wonderful spirit,
it is such a pleasure to read your postings!