Thanks for writing.
You also informed me (not posted) that your friend moved 5 months ago because he wanted to get away from his ex who cheated on him. He also moved to try to pursue a new career path.
Your friend will have to prove that the mother is unfit.
If he can't do that, he's blown it and can expect that the mother will likely get sole physical custody, and perhaps sole legal custody too.
When a parent moves 2000 miles away from his/her infant (regardless of how much she/he hates the other parent), the message about devotion to the child is pretty clear.
Many parents go through hell to stay connected to their kids. Your friend was not willing to be near the mother due to his own hurt feelings, and a court won't care.
If the mother is unfit, I suggest you purchase a couple books for your friend, so he can build his case to take custody away from the mother. You can see what I suggest in my Recommended Books
But, her attorney can always ask the rhetorical question, "Well, what sort of father would leave an infant in the sole care of a so-called unfit mother?! This is ridiculous!"
For the sake of this child, I strongly suggest that he move back to Chicago and try to get court orders for regular contact with his kid and take seriously the role of father (i.e., more than simply making $$), which will be most important to the child.