Divorce by converting to islam

This sounds crazy but my brother in law is trying to do this, my sister in law received papers from him where he has filed for divorce from her, in the 1st Sharia court in Cotabato , he is an American and has converted to Islam, at least untill after the divorce, my sister in law is Catholic, I thought this will never work, but I found an article where the supreme Court of the Philippines has unanimously ruled in favor of a husband who divorced his Filipino wife a Catholic in Sharia District Court ,I am waiting to see how this works out

Im told that when married in the Philippines(which I unfortunately did)One can only apply in the Country you married in,for anullment or a Divorce. As I enquired at our Court here in South Africa,for a Divorce and was told it not allowed.
Where was his marriage taken place?

He was married in the Philippines ,but not a Muslim wedding it was a civil wedding

Well I have French friends who are not muslims and they married in the Philippines with catholic women and they were allowed to divorce in France.  The divorce was recognized by a judge in metro Manila
Since the time of Marcos Muslim philipinos can divorce.