Our son, who is Catholic, wants to marry a non-Catholic woman who has been married and divorced. Does the non-catholic need an annulment?
The answer is a definite maybe. You have not provided enough information to give you an exact determination.
Only a Catholic is bound to marry according to the form prescribed by the Catholic Church (i.e. before a Catholic priest or deacon and at least two additional witnesses) unless dispensed from this requirement by the bishop or his delegate.
However, the Church does recognize the marriage of two non-Catholics, or a Catholic who has received a dispensation from form and a non-Catholic, whether they marry in their own church/or non-Christian place of worship, another church or in a civil ceremony (justice of the peace) as long as the ceremony is valid according to civil law.
From the perspective of the Catholic Church, therefore, non-Catholics are considered to be validly married persons unless the former spouse has died or the marriage has been declared null by the Catholic Church.
There are different types of annulment cases, depending on the circumstances of the previous marriage . Some are easier and quicker than others. Documentary cases, which include Absence of Form and Ligamen cases, are the simplest type of case and usually take only a few weeks to process. These cases are fairly easy because they can be proven simply with the presentation of the correct documentation. However, these processes are only able to be used under very specific circumstances.
Formal cases require an autobiographical essay, witness testimony, an interview, and possible review by an expert counselor, so they tend to be more difficult and often can take longer to complete once they have been filed.
It would be best to make an appointment with one of our priests or deacons so that they could understand the particulars of your son's case and give you a better answer.