The consequence of this spotting is miscarriage. And the only way to be sure is to wait and watch. Some people progress from spotting to heavy mensus and passing out the fetus. Some have spotting for a day or two..and that's it. They will then have a normal pregnancy.
Duphaston is a progesterone derivative that helps to maintain the pregnancy. There's no clear cut studies to suggest that it is beneficial but it is a common practice for OBGYN specialists to prescribe such medications to ladies who have spotting in the early pregnancy.

If your doctor has done a scan and has mentioned that the fetus is not so stable, you have to be mentally prepared for a miscarrige.

Once again, only time will tell. Do go back to your doctor if your wife's bleeding becomes heavy or she starts feeling lower abdominal pains.
Avoid all sorts of chinese/traditional medications despite what your relatives may tell you.