Wellbutrin XL is a time released medication lasting 12 to 24 hours depending on which one you are on. You do not want to chew this medication as it could cause other problems. Tell your brother that this medication could make him very sick. It is not perscribe for him. It is not a recreational drug. If your afraid your brother may take them, hide them where he can't find them.
I would not chew this med. It's not made to be taken that way. If your afraid your brother is going to steal your meds try to hide them in a safe place.