It depends on the context; if there is a choice eg. between a cranberry muffin and a banana muffin you would say, "ça m'est égal", but if you are not concerned about something, like watching "The Interview" you would say, "je m'en fiche". So, for him, it would be "il s'en fiche".

Pour ma part, j'aurai plutôt dit, " il ne s'en préoccupe pas " donc ça serait " se préoccuper de..."