Photos?
You're running into two problems. One is, you're printing in ABS, which is always a tricky proposition.
The other issue is a more general point: people think that 3D printers can "print anything you can think up", and that's not really the case with consumer-grade FDM machines. As your parts get more complex and less designed with printability in mind, you will have to get into resectioning and reassembling parts. Not just for size considerations, for printability. With a good solvent cement and some minor finishing, you can get very good results.
If your friend's model is not too proprietary to share, perhaps you can upload your factory file and we can make some suggestions.