Yes, most likely a Roth is a good way to go. That way no matter what happens in the future with your economic situation, the economy as a whole, tax rates, etc you know that what you see in the account is what you get to keep. If his employer matches his 401k contributions you already get a little bit of a hedge because the employer match will always go into the pre-tax (traditional) 401k account. So you are likely building up both pre-tax and Roth money.