The headline is a bit misleading. Anyone who actually thinks that Apatow gained his reputation mainly on stoner jokes doesn’t really know his work. Even his more straight-forward comedies alway had heart to them.
Also, I haven’t seen it, so who knows, but I feel like it’s pretty unlikely that it’s actually “casually revolutionary in its treatment of topics like immigrant identity, life-threatening illness, and dating across cultural lines.”
Believe it or not, not all immigrants are dark-skinned, and dating across cultural lines (ethnicity, religion, etc…) has been a part of movies/stories since forever (Fiddler on the Roof?). Even if you’re just looking at Southeast Asians, I feel like the “my parents want to arrange my marriage while I want to marry for love (and, potentially, outside of my ethnicity” theme is pretty common. I can think of two shows that use it off the top of my head (Big Bang Theory and The New Girl).
Either way, the push-pull between identities is probably the single most defining feature of immigrant stories (The Namesake, anything by Ha Jin). . As for life-threatening illness, I don’t know — but, again, people have been making movies about this stuff since forever (Philadelphia, 50–50).