Hi Jennifer...so sorry to hear you're still having pump issues. Glad to hear your son is back on MDI and is at least getting some relief and good numbers. A few things come to mind:
1) he IS getting some insulin, obviously, or his numbers would be sky high, much higher but obviously not enough..why, site - set - incorrect doses? Also, i've been told too that Apidra only lasts 2 days and tends not to work as well in pump, not sure if you're using apidra.
2) a spike and drop can happen anytime during the night, which can also lead to liver dumps and can cause very high highs in AM, can you get a CGM or at least a trial, this could be really help?
3) I too am very lean with muscle and was always told to use the smallest, shortest cannulas (as well as with syringes) not the reverse as we're aiming for subq, which is the first layer under skin, before we hit muscle. so, maybe wrong sets for your guy?
4) Dawn phenomenon can happen at varies times. I believe it's different for many, some say it starts at 1AM, some say 3AM some say, my endo, it can be when someone actually wakes up so maybe 8AM. I've also been told and read many things about when to increase basal rates to off-set DP, 1 or 2 hours prior, think it takes trial and error with that. But, if back on MDI and he's doing good, then that says something. Checking at just 3AM won't show what may or may not be happening.
5) It's been my experience you don't need a new Rx to get new sets, you should be able to get samples and whichever work, just order them.
Best of luck to you. You need a break. :) Happy Holidays!