There is another trick that I have used many times.
This is easier to do with the Ping than the MM because the MM has a sealed cartridge. The Ping does not.
Take out the cartridge and disconnect the tubing, Pull back on the lunger to introduce a large air bubble in the cartridge,
Then reinsert the cartridge in the pump and pretend you put in a new cartridge.
The only issue is that you must keep the pump up so the air bubble is at the top and wont be introduced into the line.
I have gotten 15 units doing this, The pump will continue to deliver even after the cart is empty and you can keep it going as long as there is still insulin left in the line. My 23" line has 7 or 8 units and the cart usually has close to 10 in it when it reads empty.
That is close to an entire days worth of insulin if I wanted to keep my pump standing up the whole time.
A few times I got into situations where I was out of insulin except for the remainder in the tubing so I removed the cartridge from the tubing and pulled in air into the cartridge and re installed. Back in the pump the air in the cartridge pushed the air to force the insulin.
Now for the con's of doing this: One must be aware visually of the tubing (you can see the air/insulin line) when the insulin is gone, because at some point you'll be injecting air (subcutaneous air injection is not dangerous as IV would be). Also the air cushion will create a somewhat inaccurate delivery but in my case it gave me 6+ or more hours of basal to get back to an insulin bottle.
ONLY in an emergency!
Not sure what kind of pump your son has, but Medtronic pumps are not actually empty when it says no units left. There's about a 15-20 unit cusion still in the reservoir. So as long as you're not getting the "no delivery" alarm, then the reservoir isn't empty and you can still pump and even bolus some.
Once the reservoir is truly empty, the "no delivery" alarm will keep beeping.