If the problem is actually an ECM the ECM and the TSSM are electronically paired. There is, however, a handlebar switch controlled process to mate an ECM and TSSM that don't know each other. It's a pain in the ass but it can be done. If your buddy does go that way just tell him to search eBay for a listing that have an ECM and a TSSM from the same bike. I've seen them listed that way with some regularity.
The Thundermax option suggested is also a consideration. I'm not a huge fan but, if an ECM is the problem, it would get him going and would do so without to be concerned with TSSM pairing.
As was also mentioned, don't discount the various other sensors, connectors, etc. It's worthwhile to look inside the ECM and its plug for bent pins, green crusties, etc. The cam position sensor is a moderately common failure item and it will often fail without throwing codes. So when you're wondering the easiest thing to do is just throw one in and cross your fingers. Even better pull the sensor and make sure it's not all gooped over first.
Good luck.