Just a disclaimer that as a licensed real estate professional in the state of Michigan, I can not and do not provide legal advice. You would need to consult a law professional for legal advice and guidance.
I think you got some good answers on here. If you are in need of advice from an attorney I would recommend Wutz Law Firm, they are a good group of people ask for Brian.
Here is a link that may help http://www.wutzlawfirm.com
If you or someone you know are in need of assistance from a Professional Realtor any of us who participate in the free Q&A on Trulia would love for the opportunity to work with you. Are you in the market for a new home yourself?
The lender is likely going to require that you sign the mortgage, whether you are part of the loan qualification, or not. Michigan is a dower state, and thus you have inherent dower rights to the property. You need to speak with the loan officer and the title company, but I believe you will find it to be a requirement.
Best of luck to you both.
Derek Bauer, Associate Broker
Real Estate One - West Bloomfield