The simple answer about needing to file now is no -- but it would be much simpler for him to file right now and obtain service of the petition on her before she leaves. Otherwise, you would need to find a way to serve her in Taiwan, assuming you could find her there. So, yes, get started now! He does not have to finish the divorce before she leaves, he just needs to get it started and get her served with the required documents.
As to your second question, the baby. Absent someone adopting the baby, your son could be financially liable for support. It does not matter whether he sees the child or not -- child support and parent-time (visitation) are completely independent of each other.
I presently have some openings available, and can assist your son, should you want. If so, please telephone for an appointment.
David R. Hartwig
801-486-1715
Answered on Jun 07th, 2016 at 12:47 PM