2 people, editing 1 patch, on 1 computer

…is this at all possible?

( at the same time )

One starting point could be versioning your patch, e.g. with https://github.com/

If you work in different subpatches it is perfect.

But the problem will still be, how to merge your two different versions of ONE .v4p-file. As there is no merge-tool which works with nodes yet, this will be quite difficult, too.

but perhaps the workaround with subpatches works for you?

check: multiboygrouping