Since party hunting (aka within "earshot") is legal here in WI, I would tag for him if he lacked antlerless tags IF....

We were actually coordinating our hunting in some way so that we were actually party hunting, not merely hunting near one another without any sort of "group" to it...

AND IF we discussed the matter in advance. If he shot the doe without a doe tag or an already verified available and legal tag, my answer would be no.

If I lived in an area where it was illegal or it would occur in a manner which would be illegal here in WI, my answer would definitely be no.