It depends on the level of activity of the foreign author:
If the author performed a limited part of the work (e.g. ran some statistics), and the paper does not acknowledge any foreign funding, you should be prepared to answer a question regarding the author’s role but don’t need to do anything else.
If the foreign author acknowledges funding for his or her work limited work, that funding should be included as Current and Pending Support or Other Support for the PI in proposals and progress reports
If the work done by the foreign author is significant then it constitutes a Foreign Component, which requires prior approval by NIH. If the foreign collaboration was described in the funded proposal, it is already approved. If it was not in the proposal, prior approval must be requested from the grants management official before initiating the collaboration.