The only way I can really convey what I'm asking here is to tell a [fictitious] story:
Chaim Yankel is a late-hour delivery driver for a company. Since he works before daybreak, his schedule is much different than your average person. Here's how his day goes:
Chaim Yankel wakes up at 5:30 pm, the time in which most are getting off of work. He shows up to work at 9:00 pm, and works from 9:00 pm until 6:00 am. Then he gets home at 7:30, and sleeps until 5:30 pm, where he starts his routine over again.
My question is, how would this Chaim Yankel daven? Would he daven Minchah/Maariv when he first got up, since it would be around that time for normal people, or does he daven Shacharis when he wakes up, even though it's evening time?