Unless you volunteer more information, it is hard to help you.
Is it on a single ticket with just a brief layover in HK that you use to visit family? Which final destination?

CX is "obliged" to nothing by HK laws. But that also depends on the destination. If you were flying FROM EU/UK you would be entitled to a few benefits/compensation even on a "foreign" airline, but not on the way to EU/UK.

It never hurts to ask for free hotel. CX sometimes do. Although you will have to checkout the hotel around 3am or so.