Tyler was involved in a car accident and has been put into an induced coma so that he can heal. Induced coma is sometimes necessary to reduce the swelling of the brain when the brain is injured. It's usually the last resort in an attempt to reduce brain swelling.
I think back to the time I felt helpless when my uncle was unconscious, and I believe this is exactly what Ryan is going through right now.
It is obviously a very, very difficult time for Ryan, Ty's brother, so I thought I'd encourage you all to drop a positive message at Ryan's blog - to both Ryan and Tyler. Ryan will read messages to Tyler to him, and although induced coma decrease the metabolic rate of the brain significantly, it does not shut down the brain, thus I believe Tyler will be listening.
If you're a religious or spiritual person, keep Tyler and his family in your prayers and thoughts.