As I understand it this is a exception to the regular policy:
Is it possible to transfer my season tickets to any person?
The purchase of season tickets is not a property right but rather a privilege that is assigned annually to you by the Michigan Athletic Department. Season ticket holder privileges may only be transferred to a spouse of a season ticket holder, or to the surviving spouse in the event of death. Such privileges cannot be transferred to children, colleagues, or friends of a season ticket holder.
I believe #1000SSS allowed this around 5 years ago or so and it looks like it is back on, once again with a required donation of $500 per ticket to make it happen. Deadline to take part is February 15, 2013.