"The woman's son is holding his mother."
Translation:Kvinnans son håller i sin mamma.
V2 doesn't always mean the 2nd word, it means the second 'position' in the phrase. Here, the first position is taken by the subject of the sentence: "kvinnans son," (the woman's son). The verb follows in the 2nd position: "kvinnans sons håller..."
"Kvinnans son" describes the subject, which is a person. Both words are needed to define who the person is, so both words occupy the 1st position in the sentence, before the verb.