2000 Jetta immobilizer??

Sup guys..so this chic i know got some weird and unusual problems with her jetta..sometimes it will start and sometimes it wont (starter doesnt engage) dash lights flicker and what not. also sumtimes it will be driven for a few minutes and then suddenly stall and not start for like 15minutes. and even unusually enough she will walk away after driving it and the radio (factory monsoon) will turn on and play music without keys in the ignition. she took it to a local VW dealer Visions..and they charged her $800 and held the car for 2 weeks only to change her coils and w.e else which apparently wasnt the problem. i did SOME research and came up with faulty dash cluster and immobilizer issues and keys and key ignition coils going bad. im curious if any of u guys had this problem with ur car and if u could be any help in maybe what specifically could be wrong. id appreciate it