Man oh man.
Dough, this is hard to read. I mean, I can't believe this is happening. Yes, he divorced your mother, but he should still be in your life and want the best for you. Seems like he does, but with this last letter....it's just seems when it comes down to it he wants more money for himself.
I think there are some things you didn't explain to your father, or that he dosn't understand.
1) Getting an engineering degree ISN'T EASY....did you explain this to him. Yes, I've heard of many people getting HARD degrees that exceeded the "norm" graduation date.
2) Does he know you have a job and are working while going to school?
3) That you are in a LONG DISTANCE RELATIONSHIP. I'm in one now, and it's hard, I want to be with her and hanging out and have fun, but we've both talked and she says that it's best for me to finish college (1 more year, hopefully not longer). We are working together and talking on the phone every night and making an effort to see each other every couple months....(i.e flying to visit.) Anywho....my point is...it isn't a walk in the park in keeping up a long distance relationship.
4) You have ALOT of stuff going on, and this only complicates it even more.
I think he needs to man up and continue to be there for you financially until you finish and are financially stable on your own in your own place, in your own future job. Not this other routine that you are in at the grocery store and going to school just to finish. It isn't like he needs to be paying till your 45. Just a couple more years, I'm guessing 3-5 max. Maybe I'm over....but just a guess.
I'll be praying for you Dough,