Excessive amounts of starting fluid, or ether, can wash the cylinder walls down very quickly and this can lead to low compression, which on a flathead is pretty low even on a good day.
This could be why the engine appears to crank over easier than it did previously; assuming the piston has not disconnected itself from the connecting rod of course.
Remove the plug and crank the engine over slowly just to verify that it’s going up and down.
If washed down cylinder walls is the cause try squirting a small amount of motor oil into the cylinder and then see what happens with it.
(I worked for a dealer once who had a pretty dumb lot man and one of his duties was to start every car on the lot in the morning to make sure there was not a problem. Ether was his best friend and one morning a very low miles Dodge would not start at all.
When cranked the engine would turn over very easily and a compression test showed all cylinders were about 50-80 PSI and at which an engine will not run. A squirt of oil in each cylinder, reinstalled the spark plugs, and it fired right up due to the oil helping to seal the rings up again. A followup compression test showed about 175 on all cylinders.)
Just an example to show you what ether can do to an engine and really, the only ones who should be using that crap are people who are trying to start a diesel on a cold morning, and even that’s a maybe.
In the case of the lot man I mentioned, I’d come in for work in the mornings and the entire lot would smell like ether. It was a running joke that if someone lit a cigarette up out there the entire dealership was going up in a fireball.