Can a person change Watch
However don't ever count on anyone changing for the better if they have a major fault. If they do, treat it as a bonus.
Otherwise, work on the premise that they will stay the same or get worse.
The people that are most likely to change for the better are the ones with a good starting point. The ones that already have a kaizen approach to their own lives and no major flaws. They grow older and wiser.
Think of it as people being like wine. If the wine is good in the first place it will age well.
If it's vinegar it'll get worse.