Stopping finasteride after 80 years of age

If someone took finastride their whole life and stopped at 80 would they go right to where they would have been if they never were on fin at all?

This hypothetical question is not straight forward.  First, assuming that this 80 year old man had unherited a Class 7 pattern of balding and that finasteride was 100% effective at stopping hair loss.  With this assumption, I am sure that he would revert back to his inherited pattern within a few months.