Honestly haven't seem news like Hong Kong-ers dumping their Hong Kong Dollars for bitcoin or something like that, and I don't see any "help HK protests by donating bitcoin" articles either. The help they're asking is mostly by signing petitions and such.
With that said, I can see bitcoin being really helpful if certain Hong Kong citizens are wanting to leave the country. They can temporarily buy bitcoin, and convert it back to the local currency of the country they're moving to.
The HKD is probably too good a coin for them to bother, but your comment is the best. If you have a family fortune, rather than bother with banks, move it all to bitcoin while keeping the spare minimum for the trip, and at destination only exchange what you really need for daily expenses.
Leaving is the wisest option, the central government isn't going to back out, protesters have no chance in China, just see the rest of the country*, this is where HK is headed and they can't stop it.
* Except in Taiwan, because there are Americans in the way.