1. Firstly, unless your mate is a professional or knows what he's doing.. It's not always best to be cheap and let them have a go.. Can cost more in the end. However i'd check fuses first, then just pull the instrument cluster out and replace a bulb and check if it lights up.. then if that fails, i'd be checking your mates wiring to see if he's done something wrong..
2. Ummm... What is it your asking.. Just replace the fuse if it's missing.. Previous owner prob blew the fuse and took it out and not replaced it