A certain brother in South Africa says that when Imam Mahdi appears he will be a follower of the Hanafi Madhab. Is this correct?

Praise be to Allah, the Lord of the Worlds; and may His blessings and peace be upon our Prophet Muhammad and upon all his Family and Companions.

The claim that Imam Mahdi will be a follower of the Hanafi Madhab is not supported by any evidence. Similarly there is no evidence going against this claim.

So, Imam Mahdi might will be a follower of the Hanafi Madhab as he might be the follower of any of the other Madhabs. However supporting anything in Shariah, one needs to have evidence for that, otherwise anything he/she says is baseless as it is saying something without having its knowledge.

Allah knows best.