An in-vitro nano-swarm has the potential to revolutionize the medical field, from the diagnosis of ailments to targeted delivery of drugs. A nanobot swarm uses swarm intelligence to allow simple devices to communicate in a decentralized, distributed manner, within any given environment to achieve a common goal or arrive at an optimal solution quickly. This review discusses the different factors to consider and components necessary to deploy an in-vitro nano-swarm for targeted drug delivery to eliminate cancerous cells in the brain. It also discusses some swarming techniques that can be implemented for the decentralized control and acoustic communication between individuals in the nanobot swarm. Finally, there is discussion about the different challenges faced while deploying a nanobot swarm in the brain. This review hopes to give direction to other researchers through a comprehensive compilation about different practices and advancements in the field.