Wa `alaykum As-Salamu waRahmatullahi wa Barakatuh.
In the Name of Allah, Most Gracious, Most Merciful.
All praise and thanks are due to Allah, and peace and blessings be upon His Messenger.
In this fatwa:
1- Your uncle has no right to your father’s property.
2- Your study and marriage expenses are the responsibility of your brother if he has enough resources.
Answering your question, Prof. Dr. Monzer Kahf, Professor of Islamic Finance and Economics at Qatar Faculty of Islamic Studies, states:
Your question has several aspects.
1- For the land, your uncle has no right to it if what you said that your father inherited part and bought part is true. Your family, after the death of your father, became the owner of the land.
When you recover it, it MUST be distributed to the survivors: wife, son and two daughters. Your mother has 1/8 of it; that is 2/16, your brother has 7/16 and each of you and your sister has 3.5/16. This ownership actually started, according to the Shari`ah, on the day your father died and of course remains until now.
When your recover the land or its price, it should be distributed at the same proportion. Of course, you can recover any cost of court, lawyers, etc. that you paid for recovering it
2- The expenses of living for you, including your marriage expenses, and your mother are the responsibility of the able (from work or from wealth) siblings in the absence of father.
Your brother is responsible for your living expense. If your sister has resources of her own, she is required to share with her brother according to their financial abilities, and he is required to spend on you as he spends on himself and his wife depending on his ability until you are either married or have resources on your own e.g., from the land when recovered, even if you have to sell it.
Allah Almighty knows best.