I hate to sound cold but if it came down to moms and a friend for the anti-venom, then friend is probably about to go "paws up" cause moms is getting the anti-venom. Now if it was mom and spouse, it's another matter. We're probably all about to check outta here cause I'd split it up, feed both of them the anti-venom, and use my last strength to carry both of them to safety.
...actually I'd figure everything would be ok if I could just make it to the commercial break; cause everthing's better when you get back from a commercial.