Hello,
I apologize for not being able to do an introduction, I'll keep it short for future reference.
I ran into a unique issue that I have never experienced with a car before,

I bought a used 2004 civic 5 sp manual for my brother,

It had about 10-20% left on the clutch and was making some squaky noise just when shifting at normal speed, which I assumed was the throwout bearing. I expected him to burn through the clutch relatively soon and have to replace it and the bearing anyway. And it happened while he was driving 20-30mph and the clutch stopped engaging we had to tow the car home. All of this sounds like a normal clutch replacement. The car can be easily pushed when its in any gear. Transmission seems to be ok. etc.

However, at the same exact time as this happened, the starter does not seem to be able to turn the engine. It sounds like either it spins or its stuck, I cant tell by the sound, but I dont see or hear anything moving in the engine bay.

I immediately took the timing belt cover, because I thought it snapped, but it looks good and new, lik eit has been recently replaced.

I'm really puzzled how both of these things can go wrong at the same time. My thinking was

1. someone either replaced the flywheel with one of those cheap aftermarket parts that completely snapped
2. the clutch somehow burned out and jammed the starter or prevents it from engaging, or prevents the flywheel from turning
3. there is some kind of switch the prevents the starter from popping out (I'm assuming its the kind of starter that pops out, spins, then pops back in)
4. something locked/destroyed the engine, where it can't turn at all, which in turn caused the clutch to burn out immediately

As you can tell, 1-3 can all be fixed with cluthc replacement, 4. is not good. But since there were no loud noises, timing belt didn't shear, and the car pretty much came to a stop slowly without skidding, (all to my knowldege, I wasnt there), the engine is alright.
I am planning to take it to a shop to replace the clutch, but if the engine is destroyed, I should probably look into selling it or donating it. But i obviously dont want to spend money on one thing if I have to sell the car.

My question is.

Has this ever happened to anyone? What do you think can be wrong? How can I check that the engine is okay?

From what I know I need to turn the crankshaft (not the camshaft) using a 19mm bolt. However, it's buried deep next to the wheelwell, and I dont think it's accessible without taking the engine out.
Is it even accessible? Do I need to drain oil to get to it? Can I just turn the camshaft with a 17mm wrench?

Let me know what you think, I have till tuesday to do some diagnostics before i take it to shop. thank you all very much.

 

I would suspect the problem is that your starter motor failed.

How do you know the clutch had 10-20% life left? I don't know of any way to check that on these cars.

I've put 100k miles on a clutch in my Civic, and when I changed it, the friction disc was only about half worn down to the rivets.

But It is possible to rotate the engine at the crankshaft pulley using a socket and ratchet without really taking anything apart, taking the driver side wheel off may be the only thing to make it easier to access.

Try rotating it when the car is in neutral, I believe you should rotate it counter clockwise, but you may need to verify that.
I assume that will check out fine.
The real tests I would do are with the transmission and clutch.
To see if the clutch is disengaging, put the car into any gear, take the parking brake off, verify the car does not roll and the transmission stops the car.
Then press the clutch pedal and see if you can roll the car. Either get a friend to help or dangle your foot out the door and try to push while you have your other foot down on the clutch.
If the car does not move when in gear and clutch down, then you should either double check the clutch fluid is fine and maybe bleed the system, inspect the master cylinder and slave cylinder, or go in and take the transmission off to see what's the issue and replace the clutch.

If everything seems fine, I think your starter is probably bad. If everything is fine too, then I'd try bump starting the car. If that works, go get a starter motor.