I've had to give up liquorice. It affects my guts and waterworks very badly.
I only discovered that when trying to drink fruit teas - they contain liquorice extracts and have no warnings about it. When I contacted the manufacturer to complain about the lack of warning, they said they couldn't do it, because that would mean they were making medical claims for the tea.
As a food substance, they did not legally need to provide any warnings about the contents!

But your son's father would have found out, the
soft way.

I've found dried apricots make wonderful "sweeties", but they have similar side effects when you eat a whole packet.