بسم الله الرحمن الرحيم
(1) It is not wajib on you to pay the zakah of the jewelleries available with your wife. However, if you pay the zakah with the permission of your wife then zakah shall be paid.
(2) If your brother is poor then you may give him the amount of zakah. He can pay his fees with it after it is given into his complete possession. If you pay his fees directly then it shall not be paid. However, the zakah will be paid if your brother appoints you as his wakil to pay the fees.
(3) It is not necessary.
Allah knows Best!
Darul Uloom Deoband