To unlock Cole you have to meet his great grandfather, Emmett.
To make sure you're on the right track with them, or to read about the optional content warnings for everything going on with Adryn, for character designs and character sprites! When Emmett offers to return your handkerchief, choose option 2: "No, that's okay. You will be able to meet Cole in the present on or after Day 10.Cole can also be unlocked using the cheat code guyaissecretlyace. In the present, use your computer in The Emerald Apartment and click on the Firecat icon. The goal of a dating sim is to raise your Relationship with characters and after falling in love, to have a happy ending with them.Raising your Relationship can be done by talking to them, giving them gifts and going on dates.Play this song on the piano in The Hayes Mansion while in the past.The key pattern goes like this if each key is numbered from left to right: 8, 11, 10, 5, 9, 6, 8, 4, 3, 11.Talking to characters will increase your Relationship EXP with them.Once you have enough successful dialogues with the character, a message letting you know that you can now give gifts to the character will appear.If you have 225 Relationship EXP or less with them, you will get 1 Heart and the "okay" ending.If you have more than 225 but less than 450 Relationship EXP with them, you will get 2 Hearts and the "good" ending.