Harvard University is a private school, you pay by unit, the tuition cost is how much units you took in a year.
Financial aid is a government program in helping the US citizens or permanent residents. Medical School is a professional school, there is no financial aid, the government only subsidize the loan for the studuents. it means, the students have to borrow the money from the bank, or from the financial institutes, the government guarantee the payment, if the students do not pay back after graduation, the government will pay for them. I don't think the US government will gurantee the loan for the foreign students. For you own sake, don't expect the financial aid.
Tuition, boarding, foods, books and supplies, it will cost in the neighborhood of USD50000/year. Professional school may cost more. But, I don't think you can get in, Unless you completed your college in US with 4.0 GPA and participates in volunteer works.
Addition:
Mr. Konishi is talking about the financial aid, the grant that need not to pay back. But, it is only for the college, it is not for the professional school. Moreover, the grant is for the poor people. I am wondering there are lot of poor people in US, why his friends are so special, they can get the financial aid for professional school. The other poor US citizens and/or residents can not.