Ex rang dh crying she had no money for their child. He pays weekly maintenance as well as as extras.
Dh gave ex a lump sum of money (she asks for a certain amount)
A few weeks later ex goes on a drinking holiday without telling us - not that she needs to but obviously dh needs to know where step child is while she is gone
Dh then finds out through a mutual friend of both of theirs that the money has been used to go on this holiday and not spent on the child. He knows this because the woman that booked the holiday (it's a group of women who went) did it on the same day as the money was transferred for the exact amount she asked for (well she asked for £400 and the holiday was £394)
What should he do?