You will never see a Gulf Arab allow his sister marry another ethnicity. In Saudi a women will lose her citizenship which comes with benefits.
I am my Sister Wali my father passed away years ago. My Sister is 17 and I’m in my 20s but if she finds a good Muslim man with a respectable job and can take good care of her who am I to deny my sister happiness.
Cool.
You're sister is lucky to have a caring brother.
And may Allah bless your father with Jannah.