If I live with my brother who sells drugs, even though I don’t what will happen to me if he gets caught?

Your brother has put you in a difficult situation.  Should your brother be arrested for drug distribution, whether at your home or elsewhere, the police will most likely attempt to obtain a search warrant of your shared home.  You may be placed at a significant risk of criminal charges should they search the home and find any evidence (circumstantial, etc.) that could connect you to your borther's activites.  It is recommeded that you speak with a private criminal defense attorney to discuss your concerns.

Legally, you are not responsible for a sibling's or roommate's crimes, and there is also no duty to report another's crimes. Therefore, in theory, you would not face criminal charges or other liability.

In practice, if you live together and are related, the authorities (e.g. police; prosecutors) may not believe that you were not involved, especially if drugs are found in common areas or, worse, your bedroom, and/or if there is difficult to document money in your account or home (including from cash-based jobs), which they assume came from drug sales. Therefore, there is a substantial likelihood that if your brother is caught, you may face charges, too, and if the evidence seems to point to your involvement, you could be convicted.

There's also a chance you could be pressured by the authorities to testify against your brother; and the chance your brother will offer to testify against you (claim that you were the main seller), to reduce his own charges or punishment. And over and above that, there's the chance of violence--e.g. if a sale goes bad; if there's a confrontation with police; if your brother fails to pay a supplier; if someone wants to rob your brother because he believes your brother has drugs and money; etc.

Living with a drug dealer, especially a related one, is clearly a dangerous situation for you on many levels.