INA 212(a)(6)(C)(i) is material misrepresentation or fraud, which is a lifetime ban. He will need a waiver to go to the US. What kind of visa is he trying to get?
If he is trying to get a nonimmigrant visa, like a visitor visa, to visit, and not immigrate, he will need to apply for a nonimmigrant waiver. There is no form to apply for such a waiver; rather, when he applies for a visa and is denied with this ban being the reason, the consular officer will let him know what is the procedure to apply for a waiver, which will be adjudicated by that same officer. Note that nonimmigrant visas can also be denied for "immigrant intent" (the generic reason for denial), which has no waiver. Only if he is denied for the misrepresentation ban and not immigrant intent, can he potentially apply for a waiver.
If he is trying to get an immigrant visa to immigrate, he will need to apply for an immigrant waiver with Form I-601. He will need to show "extreme hardship", to his spouse or parent who is a US citizen or permanent resident, if he cannot be in the US. If he has no such qualifying relative, then he cannot get a waiver. (In such a case, if your mother will also immigrate, she can immigrate first, becoming a permanent resident, thus providing a qualifying relative.) Even with a qualifying relative, it is very hard to demonstrate "extreme hardship".
Alternately, maybe he could try to argue that he doesn't really have this ban, that the misrepresentation wasn't "material" to the adjudication of the application. However, consular decisions are non-reviewable, and it's very hard to convince them that they are wrong.