Hey Yufei,
You're in a pickle! Your dad sounds like a very pragmatic sort of guy. Normally I'd say you could cite the bunches of studies that correlate the study of music with increased academic performance and capacity to concentrate.
Such as:
https://www.apa.org/news/press/releases/2019/06/music-students-score-better
https://blogs.scientificamerican.com/observations/your-brain-will-thank-you-for-being-a-musician/
There's quite a bit more, Google is your friend! "Studies Musicians Improves"
However, since you ALREADY play an instrument, your challenge is also convincing him that electric guitar is just as valid as violin, or even MORE valid.
I mean electric guitar instruction is usually less expensive, so that's one avenue of approach.
Also, the average salary of professional violinists is pretty dismal; somewhere around $32 an hour, and keep in mind that's after huge amounts of formal education and succeeding in a very competitive atmosphere. So it's not like making money from guitar is really any less practical an option. (Though neither are recommended when it comes to paying the bills.) So it's not like you're losing a big financial opportunity by moving to a different instrument.
HOWEVER, more interesting is... If you already know and are interested in computer sciences, there are a LOT of applications of computer science in the realm of electric guitar: There is a huge market revolving around studio plugins, modeling software, teaching software (like Wyzant), etc that is much more relevant to an electric guitarist than to a violinist.
That is because electric guitar is still an instrument which is on the forefront of innovation, and especially on the software end of things. People are always looking for new ways to get a great sound, whereas with violin;
"Stradivarius/Steiner/Guarneri did it best hundreds of years ago and nothing can ever be better."
How many guitarists have bought or used Apple's own Garageband or Logic Pro versus violinists? Nevermind the plugins, where I'm sure violinists make up less than 1% of the user base.
It's your argument to make, but if you're going to look at which musical instruments are most relevant in a modern sense, and which instruments you will want to know if you want to strive towards any sort of work in the musical software industry (which is huge): electric guitar, keyboard/synthesizer. Definitely the big two.
Think you can convince him you want to become a software engineer for a musical instrument company, and THUS you are interested in electric guitar? It's a stretch, but hey.
Just maybe.