Hi,
My friend won't be able to write you a recommendation. What he will be able to do is submit a referral. The referral will inform the admissions committee that you're a domestic applicant and therefore eligible for certain grants and fellowships. The admissions committee will probably already realize that you're a U.S. citizen from your application, but a referral may help get their attention.
I just finished up the bioengineering PhD program there, so I am no longer a student. But my friend in electrical engineering is still a student, and he will be able to make the referral. I've really enjoyed the program here. I developed some great working relationships and connections within the university and also with local industry. I had a great fellowship package that provided a stipend that was greater than most other schools.
PM me if you want my friend to submit your name in the referral program. Just send me your full name, the name of your undergraduate institution, and your email address.
Good luck with applications.
-David