While i'd suck up and live with an extended layover in HKG, I think the OP's well in his/her right to be mighty annoyed at the forced overnight layover, without any assistance, in SFO.

OP: I think you should contact CX, be succinct (imho, your post was, but perhaps beeven more to the point, highlighting what the biggest grouse is).

My folks aren't quite 75 yet, but i would be really annoyed in this case and be firm, but polite. Perhaps pointless, but I might add a line that it wouldnt be wrong for CX to send an apology note (your dad probably doesn't care for compensation, but this might matter).

Glad your dad (seemingly) got through all fine- I routinely ask for special assistance for my mom when she is travelling alone - just so that things get highlighted if there's an issue.