Hi,

You could consider contacting Alpha Phi Alpha's National Headquarter's? They should be able to point you in the right direction if you tell them the chapter et cetera (http://www.alphaphialpha.net/). Their homepage will lead you to an address you can write to or a phone number you can call. Also, you might try seeing if someone at the African American Council on the college's campus can lead you to a member of the Fraternity that can help you out or point you on the right path (plus, I'm sure they'd love to see a photo of some of the Brothers that had been there when your grandfather was there if you're willing to share it with them)--http://www.uiowa.edu/homepage/search/index.html and click on African American Council

If you're not in the state, you might also be able to connect with some of the members of Alpha Phi Alpha at a campus near you. They might know someone you could contact that would be able to assist you.