Locked out of an 02 X5

[coupenut]

I'm new to this forum and X5s (but not BMWs) and I have a problem with a the 02 X5 belonging to the son of an out of town friend who's here in the area attending college. Here's the situation:
- 02 X5
- When key is inserted in the lock it just spins, not resistance, no contact.
- The remote lock buttons on the key don't work, the key is less than a
year old.
- The central locking button on the console doesn't function. Didn't work
before this current situation.
- The handle on the front door on the passenger side is broken.
- The rear door on the passenger side wouldn't open prior to this situation,
regardless of the position of the child safety lock.
- A new aftermarket stereo was recently installed by an installer of
unknown skill.
- I suspect that the battery has run down although I can't get access to
verify this. The battery is also less than a year old.

Any suggestions about how to rectify this situation would be greatly appreciated. I am aware of the "hard reboot" access method but I'd like to avoid that if at all possible.