The only relevant language I could find in a quick look is:
§ 61.15 Offenses involving alcohol or drugs.
...
(c) For the purposes of paragraphs (d), (e), and (f) of this section, a motor vehicle action means:
(1) A conviction after November 29, 1990, for the violation of any Federal or State statute relating to the operation of a motor vehicle while intoxicated by alcohol or a drug, while impaired by alcohol or a drug, or while under the influence of alcohol or a drug;
(2) The cancellation, suspension, or revocation of a license to operate a motor vehicle after November 29, 1990, for a cause related to the operation of a motor vehicle while intoxicated by alcohol or a drug, while impaired by alcohol or a drug, or while under the influence of alcohol or a drug; or
(3) The denial after November 29, 1990, of an application for a license to operate a motor vehicle for a cause related to the operation of a motor vehicle while intoxicated by alcohol or a drug, while impaired by alcohol or a drug, or while under the influence of alcohol or a drug.
(d) Except for a motor vehicle action that results from the same incident or arises out of the same factual circumstances, a motor vehicle action occurring within 3 years of a previous motor vehicle action is grounds for:
(1) Denial of an application for any certificate, rating, or authorization issued under this part for a period of up to 1 year after the date of the last motor vehicle action; or
(2) Suspension or revocation of any certificate, rating, or authorization issued under this part.
To me, it sounds like a discretionary call on the part of the FAA
if it was a drug or alcohol-related suspension. You'll probably want to call your Fed, however, once you get the full details. If the suspension was for some other reason (failure to pay child support, accident without insurance, etc.) he may be fine, so long as he has a passport or other sufficient photo ID.
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@rusty: We have no idea why the prospective student wants to learn to fly. For all we know, he's a doctor who just bought himself a Columbia and has no intention of making a career out of it.