Also, it is possible that the drug company may have a program to help those who can't afford the meds. My son didn't have prescription coverage and he has ulcerative colitis. His doctor gave him some samples and signed him up for a compassionate program with the drug companies. He now has coverage and is doing well.
I agree that writing all your background and symptoms down will help. I have heard that the best diagnosis is a colonoscopy so do discuss your financial concerns and if he can do it just with the colonoscopy all the better. Something I keep forgetting to ask but is so important is "When should I worry?". It's good to know when you should be concerned and come back in or go to the ER.
I'm not sure what you should ask your doctor, because your symptoms should speak for themselves. Bring in a piece of paper with you that lists all of your signs and symptoms and mentions your strong family history so that you don't forget to tell him any important details. He should feel around your stomach and ask you questions. Tell him how frequently you have diarrhea, the consistency, the color (these are all very important so that he will know if there is bleeding going on in the colon or small intestine). Tell him if your pain is worse after eating, or if it is worse in the morning, or at night, etc. Researchers believe that crohn's has a genetic factor to it, so it is totally possible that you have crohn's or ulcerative colitis.
***If it is possible for you to get insurance any time soon through your employer or other such ways, please do! Treating crohn's is very expensive. To officially diagnose crohn's, the doctor may need to do a CT scan and/or colonoscopy which cost thousands of dollars! My crohn's medication is $1800 a month, so if I did not have insurance I would not be on this medication. If it is possible for you to obtain health insurance then please do so before you see the doctor so that the insurance company can not deny you based on a pre-existing illness clause. Of course, I don't want you to put off seeing the doctor for a large amount of time, either because that could cause other health complications. Best of luck to you!