They are both very good actors. Needless to say, Andy Lau, one of the four great kings, put his hardcore strength there regardless of his singing and acting skills. Andy became famous as a young actor and an acting school among young actors.
The age gap between the two is also appropriate. It is also natural and appropriate for Andy Lau's post-90s generation and Andy Lau's post-60s generation to play an old man and daughter-in-law.