He is going to have to learn how to deal with his Korean parents on his own, to be honest. You cannot do this for him. You cannot teach him how. I'm assuming that he's been living in a Westernized country for many/most/all of his formative years, so he knows that there are other kinds of relationships between parents and their adult children.
You should go to Viki.com and watch some Korean dramas (they have subtitles) to see some of the melodramatic (and comic) stereotypes of Korean family life and familial expectations. Having Korean in-laws will be a major cultural shock for you. If you try to maintain what you consider to be normal (aka Western) in-law boundaries with his parents, they will feel very shut out and estranged by their daughter-in-law (hypothetically you).
Not all Korean or Asian parents are this way, but it sounds like your bf's parents are among the strict, overbearing type. I'm surprised you haven't mentioned that his parents would rather he break up with you and date a Korean girl...
My parents have been the overbearing, strict Korean parents, and it took me over a decade to get them to back off and respect that my life = my choices (and consequences). It hasn't been easy, but it was my choice, that I always knew I would have to battle since I was a teen.
Amongst my parents' friends, they have one whose son married a white American girl. She gets along with her Korean MIL, and they seem to have a good relationship, but that Korean MIL confesses to my mom that she feels like she has to treat her DIL as a "guest" and not "family" when they get together. My own mother does not know how to be comfortable with my brother's Korean wife, because it's a generational gap, and the way my mom was treated as a DIL is not something she wants to perpetuate, but her expectations are still very old-fashioned.
There's another Korean-American son of some family friends. He dated a white American girl for over 5 years, but his parents never accepted their relationship. So they broke up. My mom thinks this was the "right" thing to do, shows what a "good son" that guy is. Me? I thought "are you kidding me? that poor girl found out that her bf of 5 years can't stand up to his parents. too bad it took her so long to find out!"
He agrees but seems complacent for the time being.
He's 29. I don't think you should wait for him to stand up to his parents, at least not for you. He should figure it out for himself.