BCM Grounding issue?

So, we just bought this car yesterday and came home to find out why it doesn't run. We pop the hood, look inside, they've disconnected some things. Okay, no problem. We throw a battery on, and I turn the key, and nothing happens. No connection, nothing. Somewhere in the fiddling with process, my dad pressed the BCM against the battery. Like physically pressed it against the battery. And that made the car's lights come on, key turn, didn't crank for but there was every light in the world on the dashboard. My dad suspects that it's a BCM grounding issue because there's no way it should be making the car's electricals work by pushing the darn BCM against the battery. Thank you for your time.