From experience, I can tell you to read the fine print VERY carefully -

different policies kick in at different times as it relates to when the delay/disruption begins/ends.

keep all documentation, absolutely everything. I fought for months to collect one claim. The insurance company refused the claim because they wanted a boarding pass to prove I actually took a flight. (the ticket receipt and a letter from USAirways was not enough?)

Should your plans change due to parental illness, be prepared to work thru a lot of documentation with their doctors. A close friend had to cut two separate vacations short due to her parents' health issues and the claims required considerable paperwork.