I would be asking them why they want to SIE. Let's face it, some folks just weren't meant to be aviators and there's nothing wrong with that. Guy in my class SIE'd and the main reason was he realized he wasn't going to have as much time with his kids and family as a flyer. That was a good reason to me. Make sure your bro's talk to their family and FLT/CC about this decision. They will often provide a different perspective.
Now on the other hand, if they want to get out because they don't think they can master the flying thing or for another goofy reason, have them take a step back and look at the big picture. The IPs will decide if they can't be a pilot. UPT is not real flying.
UPT is a one time shot. Once you SIE, there is no second chance. If they can live just fine their next 60 years not regretting SIEing, then maybe it is a good decision. If being an AF pilot is something they have wanted since they were a little kid, shoving the SIE off the option table is a good idea.
Take it from someone who contemplated the SIE due to a bunch of personal/family issues that resulted shitty performance for a few months in UPT. It's probably not a good idea.
I got my #1 choice at #1 location and am living the American Dream. I cannot imagine what it would be like if I had gotten out...
Anyone reading this thinking about SIEing, feel free to PM me about it. Can give you my story and a those of a few bros who got out. You will think twice.