u can ask things like "how is work?" or start something related to the news, or something to do with their hobby. usually this kind of topic will bring up discussion. ask ur bf what ur parents like and do a bit of research about it. if u dont know much about the hobby, u can start ur conversation like "uncle i heard that u like to do...., may i know how it works?"

btw, dress nicer (proper), be careful of small manners & bring some small gifts too. i'm somehow careless and my gf's parents thinks negative about me now

things like chicken essence, bird nest, or some nice biscuit etc is good, try to check with ur bf about their likings? if u buy food then should get something that they can enjoy it later. as long as u fit well into the culture and show ur caring to them should be ok. not sure this will apply to ur bf's family but details like take food for the parents (during meal) is good for chinese family. hope u can score their hearts cant really give u much advise. hope my tips help.