He left behind some incomplete songs that his friends (Glen Hansard, Colm Mac Con Iomaire, Gemma Hayes, Lisa Hannigan, and so on) completed. That work would be his only solo album after his band The Mary Janes split up, the LP Skylarkin. It's a surprisingly uplifting album and transcends time and even his own life. He's still at work. I encourage you to listen to Skylarkin today. If you don't have it, buy it. Don't download it.
Rave on, Mic Christopher.