dealer says car cannot be fixed

[rgmrgm]

trying to help a friend sort out a 2003 540 v8, if you hold the key in the start position for 15 sec or so the engine starts and runs fine. trans shifts ok but will not go into overdrive. windows will not work, no speedo or tac, all warning lights are on, no radio, no heater or ac, no signal lights, temp indicator goes to max. The car had its computer stolen(the one behind the glove box) bought a new computer from the dealer and dealer installed it and a new connector. two months later the dealer says there is a short in the can bus and the computer will not communicate with the other control units and said they cannot fix it. took it to an independent BMW specialist who initially said he could fix it, said he did a pin check, ground check , pulled a bunch of codes dealing with control units talking to each other charged me $200 and said he cannot fix it. have we reached a point were cars electrical systems are so complex they cannot be repaired? any suggestions?