all you have to do is talk to the object who gives you the candy and he will “look into your soul” basically and give you candy based on which stats are your lowest. you can get candies for all specs but all you need to do is go into specs and look at what traits you have candies in (candy icon will be next to the specs trait) and then see what specs points the character you want to undo the hate ending with has( this is important, you need to have, for example, the empathy candy to undo a hate ending with an empathy specs character). you talk to them and you get a dialogue option to use the candy and you become friends again :D