A big issue I've come across as a person who stutters: If he needs to take care of something that could be done over the phone but would rather drive to the place it's because he's terrible on the phone. Don't try to talk him into just calling it will only embarrass him. Same pertains to fast food drive-thrus I always prefer to go in and order to avoid the drive-thru which has the same affect (effect? I never know) as the telephone. If he wants to go in and order don't break his balls.