I struggled with that one at first too! Here are the steps to unlocking it:
-Start human/witch route -Pick either: Just hiking / Came to meet you / Studying magic (doesn't matter) -Ask about his pack -Pick either: Keep going / Stop somewhere closer (doesn't matter) -Ask him to stay -Offer him any food -Pick either: It's lovely / It's too cold!! (doesn't matter)
And there you go!! Hope this helps :-) Have a nice day (*¯︶¯*)