No spark and i can only get 5V at the coil.

did he check to see if the plastic gear on the dist sheered off? and wont send a ground signal to the ecu if its not turning.

He said he verified the dist/rotor is turning on the previous page.

I'm going to agree with the bad battery diagnosis but it may not be the reason it won't start. It should rest at 12.6+ and not drop under 10.5v while cranking.

If you're only getting intermittent sparks from the coil wire itself (you should be getting quite a few of them and consistently) then there's two things to look at: voltage, which is already suspect; or the pickup in the dist. I would suspect something to do with triggering the coil, which means looking at the pickup. Some of the weird wiring, like the coil wires going in and out of the firewall, tells me that it probably had an aftermarket ignition at some point but then it was removed and they half-assed the removal. Probably also explains all the ECU splices.

Take some pictures of the inside of the dist and if you have some feeler gages (brass, preferably, since things are magnetic in there) check the clearances to the pickup.