Is this wrongful eviction?

Yes, he signed a paper consenting to the landlord's allegation of selling and using drugs on property. Whether it's true or not is irrelevant now. Only when he signed that document, he signed it on behalf of all tenants currently living there. Landlords can be tricky b@stards. This is an important life lesson your brother has learned... He probably won't be so quick to make the same mistake in the future. But no, this does not qualify as a wrongful eviction because everything was done legally. I would suggest trying to reason with his landlord. But I am not sure if that will do any good. Either the landlord wants your brother out or someone reported him and his roommates and the landlord failed to investigate and instead acted on someone's heresay. A notice of eviction is not an actual eviction. An eviction is when the police comes to your house and tells you to get out, so he still has time to see if he can turn this around.