Man that sucks. I hope it doesn't take forever to get the herd back at least somewhat decent. I guess you'll have to see how the state handles it, and if they shut down doe seasons next year, etc. We've had a couple real small run ins with EHD in the areas I hunt, but nothing like what you are mentioning. That is crazy. I guess the only positive is you should be able to find some nice skulls instead of sheds this winter. Not really a positive I guess.
Funny you mentioned CWD. IMO, that whole thing is absolute BS. I hunt in WV & VA where CWD has been found and it amazes me at what they are doing about it. I personally believe CWD has been around forever (like other diseases), and nobody really cared or worried much about it until the big buck area's had a run in with it and it threatened an economic impact. Then everyone jumped on the bandwagon, and it ain't done a thing to change it, but create headaches for hunters.
In VA in like 6 yrs of testing they have found 4 deer total. I'd be willing to bet you could test for 6 yrs for ANY disease whitetails are known to carry and find 4 that had it. WV doesn't have a ton (I don't know the exact number) but I know its very few actually considering the deer numbers in the affected county and they have been testing for like 8yrs I believe now.
I believe these diseases are just God's way of thinning out the herds, there are certainly too many deer in alot of areas. Not really complaining, I like a nice herd...its certainly better to go out and see deer most times I hunt, than when I was young and rarely saw any.
Good luck to your folks in IL.