I am going to quote to you Oregon's laws concerning annulment of a marriage. However, continue reading my answer because it may be possible that a marriage never took place. The Oregon's Annulment laws state as follows:
107.005 Annulment of void marriage; declaration of validity; effect of declaration.
(1) A marriage may be declared void from the beginning for any of the causes specified in ORS 106.020; and, whether so declared or not, shall be deemed and held to be void in any action, suit or proceeding in which it may come into question.
(2) When either husband or wife claims or pretends that the marriage is void or voidable under the provisions of ORS 106.020, it may at the suit of the other be declared valid or that it was void from the beginning or that it is void from the time of the judgment.
(3) A marriage once declared valid by the judgment of a court having jurisdiction thereof, in a suit for that purpose, cannot afterward be questioned for the same cause directly or otherwise.
107.015 Grounds for annulment or dissolution of marriage.
A judgment for the annulment or dissolution of a marriage may be rendered for the following causes:
(1) When either party to the marriage was incapable of making such contract or consenting thereto for want of legal age or sufficient understanding;
(2) When the consent of either party was obtained by force or fraud; provided that in the situations described in subsection (1) or (2) of this section the contract was not afterward ratified.
It sounds like in your son's case, however, he merely signed an application for a marriage license. That does not mean that a marriage actually took place. A marriage takes places when there is a "Solemnization" of the marriage. What does that mean? It basically means that there must be some public ceremony where the parties to the marriage declare that they will take each other as husband and wife. Again, I will quote a particular Oregon law:
106.150 Form of solemnization; witnesses; solemnization before congregation.
(1) In the solemnization of a marriage no particular form is required except that the parties thereto shall assent or declare in the presence of the clergyperson, county clerk or judicial officer solemnizing the marriage and in the presence of at least two witnesses, that they take each other to be husband and wife.
(2) All marriages, to which there are no legal impediments, solemnized before or in any religious organization or congregation according to the established ritual or form commonly practiced therein, are valid. In such case, the person presiding or officiating in such religious organization or congregation shall make and deliver to the county clerk who issued the marriage license the certificate described in ORS 106.170.
So unless a ceremony which was in accordance with 106.150 took place, a marriage was never entered into. And there would be no need to commence an action to annul the marriage because there was no marriage.
I should also point out that the marriage license that your son applied for is only good for 60 days. Read:
106.077 Issuance of marriage license; waiting period; exception.
(1) When the county clerk has received the written application for the marriage license from both applicants, and all other legal requirements for issuance of the marriage license have been met, the county clerk shall issue a marriage license which shall become effective three days after the date on which the application was signed by the applicants. The county clerk shall indicate on the license the date on which the license becomes effective. A license shall be valid for 60 days after the effective date.
I hope this answers your question. Good luck. If you want to continue to read the full text of all of Oregon's marriage laws Go Here and read Chapters 106 and Chapters 107.