The 535 won't start, gotta be electrical, help please.

[BFEINZIMER]

So after my accident I've had the car garaged, I took it out a few times, had to jump it once a few weeks ago but drove it and yea. Started it a few days ago, ran it for a few mins, then the next day it would not start. Finally got a chance to try and jump it today and it was a no go. First we hooked it up and it cranked for a sec but nothing. Then I decided to wait, took the key out of the ignition but the obc center display stayed on displaying "Fasten Belts" along with a few other dash lights. I was puzzled. We disconnected, switched sides of the cables, and repeated about 2 times but these times not even clicking. And all the while the Brake Fluid light stayed lit dimly in the dash. So I disconnected the neg terminal of the batt a few times for a few seconds each time, it went off but on each re-connect the light lit up. Well we hooked up the jumpers again, waited several minutes while revving the other car, and tried to start the E34, no clicks nothing. Any ideas please? That Brake Fluid light will just continue to drain the batt. and I have no idea why its on. Note the car does have LoJack so consider its small battery. Also, we did get a spark on connection of the neg jumper cable each time although sometimes it was tiny and sometimes it was significantly visible (what I would consider normal). Battery is also just a few months old. Thanks!

UPDATE: Went out about 20 mins later to push car into garage, dash lights were off, and when I turned the key to II some came on dimly, but shut off once I removed the key.

On the note of what I'll do with the E34. I'm accepting Farmers check, the E34 will take a salvage title, Tim and Kim are going to help me repair anything mechanical and I'll try to buff out some of the paint stuff. Then flip the wheels, tires and anything else I have a stock part for and then sell the E34 to another BMW person who want to fix it up. So yea.