Option 1 - ask him to export stems from his project (from Song menu> export stems), he can select the tracks he wan't to export , the format etc..
You can check a box to either export based on the selected loop size or with the Start/End markers.
Option 2 - ask him to export an .aaf of his session which you can import in pro tools or S1 by reaching File menu > Save as...
Then saving under .aaf format which is available in the list.
Checkout more informations on AAF files : https://en.wikipedia.org/wiki/Advanced_Authoring_Format
With options the audio tracks should remain in sync together :)
Hope this might help ,