Will I qualify for a grad PLUS loan if my cosigner has perfect credit but is unemployed?

I start grad school in a few weeks and just rehabilitated my default undergraduate loans. As it's been explained to me, after 6 consecutive payments, I've again qualified for federal aid; after 9, I'll no longer be in default. So, though I qualify now, I should remain in default until October 1.

Obviously, I won't qualify for PLUS on my own, but a relative is willing to cosign. He has perfect credit, but he is retired / cannot list an active employer.

Q: Will his endorsement be enough to qualify me for the PLUS loan?

Thanks.