From what little I know of the Philippine annulment process, this seems very unusual to me, I've never heard of the inlaws being involved in an annulment process before. If the husband hasn't contested then it's usually just procedural and based on the psychiatrist report, which if the husband has had no input is usually based on the evidence given by the applicant.
Assuming that the attorney knows that a foriegner is involved, this maybe a ploy by him or even the by the inlaws to draw things out and extract more money.