Rent or buy ? well that depends on you and your situation ... buying is a long term commitment... so do you really want to tie yourself financially to a brother ? what if after a year, he wants to move out and live with a girlfriend ? Could you afford to buy him out ? If you can't, then the house would need to be sold and that could cost you money.
Do you and your brother have the same ideas of what needs to be spent on teh house - what if you want a new kitchen because the current one is 20 years old, what if brother doesn't want to because the current one is functional ??
Are you able to put the same amount of $$ down as a deposit?
There is a LOT to consider about buying a house with someone who is not a spouse or partner.
You presumably don't work full time at present, so do you earn enough with brother to get a mortage anyway ? What if he earns 3 times what you currently do ? How do you split it ?
Do you have money for deposit, surveys etc - again can you put the same down ? If not how do you split it ?
Renting is easier if you are thinking short term - and given you don't have a full time job yet, probalby you r best option