All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger.
If that Shaykh is reciting Quranic verses that are free from charms and sorcery, it would be permissible to perform Ruqyah for her, especially if it is thought that someone did a certain magic spell to that girl to prevent her from getting married. This happens a lot. However, he should not say that she will get married after a specific period of time, as this only happens according to the will of Allaah The Almighty. In fact, Allaah The Almighty is the only One who knows when that will take place; and whether or not it will happen. The one who makes Ruqyah or treats people should simply do his part and leave the results to Allaah The Almighty.
Allaah Knows best.