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. We ask Allaah to exalt his mention as well as that of his family and all his companions.
The majority of Muslim scholars are of the opinion that writing the words of divorce on a paper is not considered as divorce unless the person intends to divorce his wife when writing.
Therefore, the three divorces written by your brother are not valid as long as he did not intend to divorce his wife. If he pronounced the divorce along with writing it then the divorce takes effect by his pronouncement. The jurists have made it clear that the divorce given in jest is effective even though the person does not intend divorce while pronouncing the divorce-words.
We entrust you to advise your brother to be patient with his wife and try your best to reconcile between them. Remind his wife of the bad consequences of separation which may even lead to the spoiling of their child.
Allaah Knows best.