Many low cost airline operators do not compensate for late departure or cancellation, the most they will do is transfer your ticket or refund the ticket price. They recommend your have international halifax travel insurance to protect you financially from these circumstances. Of course many offer their own policies online when you book.
If you intend to take the whole family on holiday, it may be possible to get international halifax travel insurance for the same price as a couples policy. There may be a limit to how many children there are on the policy.
There are often different levels of cover available that will pay out different amounts in the even of a claim. How much you will receive if you flight is delayed, may be a variable in the different cover available. Obviously the higher the payouts, the more likely there will be a higher premium to pay at the outset.