You can get his 2nd heart in Normal Logan route by finish 'I own you a beer' event. Requirements for this event down here.
- Location: Your own 'house' at Bareshade, not your own hut near a forest.
- Time: at night (after 20.00).
- Bareshade: You need to finished all Bareshade upgrade event.
- Logan: You need to have his 1st heart and also his enough likes (around 40 would be fine), you also need to help him (need Str > or = 12) during a day.
- Other conditions: You need to finished Country Road event and a fight between Logan and Barrel.
- Your own luck: This event is RNG (because first time when I'm sure I finished every requirements but it doesn't happen and when I re-enter a house again and it happen.)