Thank you for getting in touch with Enago Academy.
Sorry to know that your PhD advisor is indirectly asking you to commit research fraud. As you may be aware, data fabrication is considered to be a serious offense and can attract significant penalties, including, but not limited to, journal retractions, job loss, loss of reputation, funding sanctions, etc.
We completely understand that it might be difficult for you to talk to your supervisor directly regarding this issue; however, it would be best to have a direct discussion with him before approaching other bodies. We suggest informing your thesis committee and your institute’s ethics committee in writing about your unique situation. Many institutes have clear policies in place for handling scientific misconduct. To learn more about research fraud, please go through this resourceful post.
In case your institute does not have this system, it will be best for you to consult with other senior colleagues on the way forward. Given the visa-related situation, you could possibly involve your institute’s international office too.