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It is considered out of status not unlawfully present or not an overstay since there was a d/s on his I-94 and I-20.
*For aliens inspected and admitted for "duration of status" (DOS),
any period of presence in the United States, unless DHS or an
immigration judge makes a formal finding of a status violation, in
which case unlawful presence will only begin to accrue as of the date of the formal finding;
**When calculating unlawful presence, the date that the Form I-94 (or any
extension) expires is considered authorized and is not counted. In
addition, the date of departure from the United States is not counted as
unlawful presence. In duration of status cases where DHS or an IJ makes
a formal status violation finding, the alien begins accruing unlawful
presence on the date of the finding (i.e., the date the finding was
published/communicated). For example, if an applicant presents a letter
from DHS dated December 1, 2008, that says the applicant was out of
status starting on May 28, 2001, the applicant began to accrue unlawful
presence as of December 1, 2008, not May 28, 2001. Note that, in the
event that an IJ made the status violation finding and concurrently issued
a voluntary departure order, no unlawful presence would accrue if the
applicant complied with the order by making a timely departure.
***Overstay: Overstay means staying in the U.S. beyond the date indicated on your I-94 or the corresponding D/S (Duration of Status). Overstay is one of the acts (the most common) that causes you to be ‘out of status’.
NOTE: Persons admitted for duration of status can only overstay if found to be in violation of status.
****Unlawful presence: Unlawful presence means presence in the U.S. after the expiration of the period of stay authorized by the Immigration Inspector/Custom’s Officer at the time of entry. It also includes any presence in the U.S. without being inspected and admitted or paroled.
NOTE: If your I-94 is non-date specific, i.e D/S (Duration of Status), then Unlawful Presence begins when an Immigration Judge or USCIS adjudicator declares you have violated your status.
*****A foreign national may be out-of-status in the U.S., but may not be unlawfully present in the U.S., whereas a foreign national having unlawful presence is, by definition, out-of-status. For instance, a nonimmigrant student on an F-1 or J-1 visa who is granted “Duration of Status” or “D/S” may be out of status if not enrolled in a school but would not be accruing unlawful presence for purposes of the 3 and 10 year bars.