That is bad news. I'm praying for a speedy recovery.

I can get a bit stubborn at times. I had modified a SystemConfiguration .plist file on my MacBook Pro so the Apple USB SuperDrive would work with it. The tweak, after restarting the Mac allows a bit more current through to the USB drive, allowing it to kick in.
My reason for doing this? Easy: the MBP is normally used in clamshell mode, held vertically in a cradle thingie jigger. Such an arrangement means the slim laptop DVD SuperDrive inside is forced to work vertically & it just plain ain't happy doing that, read/write error creep in or it gets all stuttery as gravity moves the optical disc too far from the laser for it to work properly.
But the Sierra update not only reversed that setting, it added copy protection so I couldn't modify the file. First I tried using TextWrangler to do the edit, that's what had worked previously but I could only save a copy & not replace the .plist file as I had previously done. So I tried doing it in Terminal, same result, copy only. As the file I'm working with is an essential part of the bootup process, I wasn't able to replace the file.
FU, Apple. Back to TextWrangler, make the needed changes, save to desktop instead. Then boot up from my Thunderbolt-connected TechTool Pro ProToGo diagnostic SSD.
Open the MBP's desktop folder & remove the word copy from the .plist file's name. Open the SystemConfiguration folder & replace the desired .plist file making sure to have a copy of the untouched original available elsewhere.
Replace the .plist file. Restart Mac to normal boot volume.
Lo & behold! The external USB DVD now powers up and can be used again with the MBP.

Brioche Burger Buns is my new retro Afro-punk electro-folk Slayer cover band.

@kdfrawg One of the supermarkets here sells brioche hamburger buns. A strange choice, I would have thought, but it's not that bad.

//

Confirmed with a fridge magnet: the lid of the MBA uses a magnet to trigger sleep mode when closed.

Apple doesn't offer refurbished iPhones, all such stock is retained for exchange with faulty units that customers bring in for service.
Other hardware such as iPods & Macs are available as refurbished items, though.

// @kdfrawg

I had my suspicions confirmed just now: my cat has the ability to put my MBA to sleep just by being in a certain location.
The pet door fitted to the outside laundry door has a magnetic catch activated by a small round magnet that dangles from the cat's collar.
If this magnet comes close to the enter/return key on the right hand side of the keyboard whist said beastie is being friendly, then the Mac enters sleep mode.
As this Mac laptop lacks an actual latch, I'm assuming there are corresponding magnets in the lid of the thing otherwise I can't imagine how closing it triggers sleep mode.

I believe so. I've had much trouble sleeping because of gastric reflux but now it's nearly time to consider breakfast.

I gave tne ram a shove will be the name of my next Divinyls tribute band.

And I have tickled a .plist file on the two MacBook Pros so they can work with the Apple USB SuperDrive. When first released, it was intended for use with the MacBook Air. It was later that Mac Minis, iMacs, MBPs & MacBooks came along sans optical drives.

// @kdfrawg