What should I do to get married?

Dear Sister,

Assalamu alaykum wa rahmatullah,

One of the manifestations of our slavehood to the Almighty is that we beseech Him to grant us but we do not despair if He doesn't respond exactly as we would wish. Being jealous of your friends and siblings is tantamount to being ungrateful to Allah. It's like trying to tell Allah upon whom to bestow His favors. We simply can't do that. Jealousy is one of the diseases of the heart, and if we want to grow as Muslims, we have to let go of this trait. If we see that someone has something we want, we ask Allah to bless that person, we feel happiness for that person, and we ask Allah to grant us what is best for our own circumstances.

You need to look to those who have less than you, not those who seem to have more. Consider the blessings in your life: you are Muslim, you have a Muslim family, you are intelligent, and you have agency. You have food, provisions, housing, and freedom. Don't take these things for granted!

And you should also seek beauty. Remember beauty is not only the exterior. Instead, it radiates from a pure heart, a heart empty of jealousy and other diseases, and full with the remembrance of Allah. As Allah Ta'ala says, "Surely, it is in the remembrance of Allah that hearts find rest" (13:28).

Finally, I think you need to tell your parents that your sister is not taking her medication. If need be, you might want to notify her doctor, particularly if you are feeling unsafe.

Last but not least, please see the following links:
Dua for a Spouse
Marriage: Losing Hope in Finding a Spouse

And Allah knows best.