It is a very tricky situation for your friend.

Nepalese don't need any transit visa for Schengen states, if we don't have another stopover in another Schengen state.

If he is not changing airports between Paris-Roissy and Paris-Orly he shouldn't need any transit visa.

BUT as his visa has expired, he should call the nearest French consulate and gather the required information.

Indians and Pakis need transit visa if  US visa stamped in their passport is no more valid. But we were exempted from transit visa in the first place, so imo most probably your friend is not going to need the visa.