To my knowledge, yes..but only in Construct 2.
Copy/pasting assets from .cap to .cap in Construct Classic, from what I hear, can severely damage your .cap. Apparently the feature is unfinished or something.
I'd suggest taking turns with things if possible; you do art while your friend programs, then you swap places, etc.
Another thing is to make as much of your game as you can external. A custom level editor, for instance. You and another developer could both make levels, then save them as external files for later use. Or you can write in-game dialogue in a text file and read from that, instead of typing it all out in events. You get the idea.