Prius engine won't start after engine swap

I have a 2008 Prius that had a loud knock coming from the engine so I got a used engine from a junk yard and had a buddy of mine switch it out for me. I was also having problems with my hybrid battery holding a charge but I read somewhere that my battery issues could be related to excessive drag on the engine from having a bad engine so I decided to swap the engine first. It took my buddy forever to complete this project (he's had the car in his garage for like 3 months). He's a pretty good mechanic and he's swapped engines and transmissions before but he's never worked on a Prius. So he's got most of it back together. Got the engine in and all hooked up, charged the 12 volt battery, but now the gasoline engine won't start. The hybrid battery is down to 1 purple bar(but I don't think that's stopped me from starting it before), all the little warning lights are on (low tire pressure, check engine, vsc, etc...), the Red Triangle of Death is not on, there are no DTC's stored in the computer, It will switch into Neutral but not drive or reverse. There is one small ground wire that goes from the engine to a screw on the top cross member of the engine compartment which he doesn't have tightened down yet but he doesn't think that's got anything to do with the engine not starting. Any ideas??? What Am I missing???