I would check to see if State of Iowa has a website regarding CCW laws. I know Texas does. The site may have a FAQ section. If not I would check the Iowa laws about firearm access by felons. No matter what anyone says on this forum, its not the law.
txcoastie is right check it out for yourself, you alone are responcible on this one. Here in Mi you must have control of your weapon. It can't be available for a non permited passenger to access much less a felon. So on you or locked in the trunk. Your felon buddy I would think should be more worried. If he knowingly gets in the car with a gun could be in trouble. But don't listen to my speculation, do your own research.