re: Co-signing and credit scores

I imagine he would like the opportunity to boost his credit rating by adding his name to the debt and getting the financial incentives offered to those w/ better ratings.

In my experience several years back I had my mother act as the primary cosigner on a secured bank loan, and I was informed that there is no difference between the primary signer and the cosigner. On my credit listings it makes no distinguishing remarks as to primary or secondary.

You are both liable for the same debt upon default.
Just speculating from my experience about 5 years ago.