My mom is going to be facing this in 2015, and the way I understand it, the converting to Roth would require a pretty big tax payout if the IRA is of any significant amount. I wasn't aware that any of a traditional IRA (thought all money put into it was tax-deferred) would be exempt from taxation - so whatever is converted is what you'll have to pay taxes on? That would maybe explain why your FIL's tax guys haven't suggested doing this since it could potentially mean tens of thousands of dollars in taxes.
And from what I've read so far, the RMD is absolutely separate from any conversion, so they can't count a conversion as his RMD and if he does do both, he will owe taxes on both.
I wish like anything I'd known about converting traditional to Roths about 10 years ago, as I could have gotten my mom going on this and she'd not be in the same state if she had more time to convert over. :(