Sorry but I do not agree with you on this one. First of all, its a crack so there will be points where the epoxy will not penetrate, so you are relying solely on its adhesive properties. Aluminum's co-efficient of expansion alone would be a major concern. I would be only sightly less uncomfortable doing this on a steel pan.
I know he doesn't want to remove the pan, but he also doesn't want to be stuck a 100 miles from anywhere in Utah. Of the those two choices, removing the pan is the lesser undesirable. I've been to places in Utah where I would not want to have been stuck. I remember crossing a large, empty valley in Wyoming, could see fifty miles in all directions, no cops. I could go as fast as I wanted, then I remembered, there wasn't anyone around to rescue my dumb *** if I had a wreck, so I slowed down, fear and common sense.
A new or used, uncracked pan would be the best option, welding is the only other option that I see. It can be welded in place with oil in the pan BTW. We have welders that weld transformer tanks that are full of mineral oil all the time. You need to draw a vacuum first though to stop the oil leak.
Aluminum can be MIG welded, and in this case that would be the best choice, but few people have a MIG gun that can feed aluminum wire. A regular MIG gun can't do that. The only option may be a TIG welder.