If you're looking after someone who can't manage their own money because of a legal reason, this law applies to you. It says that you're acting as their agent when you handle their income. This means you're responsible for dealing with the money they earn.
You might be looking after this person as their guardian or manager. The law treats you as if you're acting for them when you receive their income, control how it's used, or spend it for them.
Remember, this only applies when the person you're helping is considered to have a 'legal disability'. This means they can't manage their own affairs for some legal reason.