Warlock NPCs Issue

The Warlock in my party, and NPC named Kaelen, when entering combat continuously tries to attack using melee weapons even with all spell slots available and Eldritch Blast as a cantrip. Franz will agree with me when I point it out, but during the next round Kaelen is back to throwing daggers. I have been asking Franz to let me take Kaelen’s turn for him so that at least I can make it make sense, but this is an annoying way to play. If you cannot get Franz to realize certain aspects of the game (such as how to target and ally for a heal spell or when to allow opportunity attacks) you should allow the player to take control of the character without having to switch from their own character. Having control over more than one character will be annoying too, but less annoying than having to correct Franz every round.