Hoo boy, do I have thoughts about this chapter.
1. The dad here is being a huge hypocrite, IMO. He's a politician, a unstable job dependent entirely on his public image, with an incredibly low success rate. Probably lower than the odds of being a relatively successful musician, actually. Seriously, how many failed politicians are out there? How many kids dream of becoming [insert political position here] and never achieve it?
2. Being a musician isn't inherently a career about "breaking society's mold". Society has a preconception about what being a successful musician looks like, just like every job. And honestly, it's kinda a trap, in some ways, at least in the digital age. You can make a living even if you're not immensely popular, if can cultivate the appropriate fanbase, or if you're willing to take jobs in the commercial sphere. Being a performing artist is a bit more fraught of a path, but still probably easier to succeed at than being a politician.
3. What career is he even picturing for her? Law or medicine would be my guess, both of which require an immense amount of discipline and grit (and a bit of luck) to succeed at. If he wants her to be an office worker, which is the job most within the "social mold", he's intensely out of touch. In Japan, that's pretty much a dead end, a very saturated job market where exploitation of workers is common.
4. He seems to be encouraging her to put all her eggs in one basket by completely dedicating herself to her career, which is a bad idea, honestly. Always have a backup plan when you're shooting for the stars. And there's nothing wrong with having a side gig.
Overall, even if he's well intentioned, his advice is severely flawed. But it's also not surprising, given the general plot of this story, either.