The letters in the second picture, they say "Bolshol Booze".
Now read them up-side-down on his tattoo.
You see two groups of numbers.
One saying "32 0 09", and the second saying "104 57 09".
What are these numbers? Well I do have a theory.
Do a coordinate-search with your favorite earth-program. I use NASAs.
Trying different ways to enter those coordinates, you will end up with the most logical, which is:
North: 32 degrees, 0 minutes, 9 seconds.
West: 104 degrees, 57 minutes, 9 seconds.
In decimals, we get:
North: 32 + 9/3600 = 32,0025 degrees
West: 104 + 57/60 + 9/3600 = 104,9525 degrees
And these coordinates point exactly on the south border of the state of New Mexico, the one facing the state of Texas.
This point is not far from the border between Mexico and USA.
I think it might be some sort of getaway-plan. That guy in the bar that gave Michael those coordinates on a piece of paper, well he seemed to be some kind of police or something. Maybe he has arranged some way for for Michael and his brother to dissapear fast and easy, starting from that location... some illegal way. That would explain why he was so damn nervous.
"If you show this to anyone else, I'm calling this of".