I would definitely pick CX in your situation, where you can earn Asia Miles on your account, your dad can earn miles to requalify for SL and a higher chance of op-up / priority boarding and other benefits (even possibly lounge access ).

The IFE on CX is surely better than what SQ offers. I wouldn't fly alone on SQ while your dad flies on CX as zhaobao suggested, since flying with friends/family is far better IMHO.


Also try other outports, booking ex-TPE is often cheaper than HKG