Map Tempo Track issue on Import (how to divide it ?)

Hi there, need some help on a project under cubase 11.

I did a tune with a map tempo, the tempo follow a live recording as i use the voice of this recording and redid the whole arrangement / instrumentations.

I sent the tune to a drummer friend who recorded the drums part of the tune in reaper on his side, i sent him the midifile of the project with the map tempo.
he sent me back a midifile with the drums recorded (Vdrums + custom Midi drumset) but the whole tempo is doubled, and so on his track too.

So of course, when i import the track in my project, it’s not in sync at all. Unfortunatly i need it too to export his track in midi to make the sheet music of what he played.

I know how to divide by two the tempo on a midi track/events using the midi logical editor but not on the whole project and the tempo track.

How can i fix that so the tempo of the tune + the drum track go back to its original state so it can play with my project ?, any idea ?
Thanks !