Why would the DI want to talk to me?

I got a call from my son today during Liberty Saturday. He just finished up the Crucible last week. He said that during family day the Drill Instructors wanted to talk to me because they had so much trouble with him not catching on fast enough. Don’t all recruits have trouble in bootcamp? I mean, he is a little bit of a space cadet, but he is smart and in shape. What should I expect during family day? Thanks!