He's a fucking selfish shit. The reason he refuses to acknowledge how ill you are, and why he tells you to "get over it", why he minimises a trip to hospital in an ambulance FFS, is because as soon as he admits you need and deserve a break, he would have to pull his finger out. Bottom line is he doesn't want to do that, doesn't see why he "should", so rubbishes the way you're feeling.
Obviously YANBU - and he should be contributing to the running of the household and childcare whenever he's around, not just when you're ill anyway. Not that he does either - useless waste of space.
As someone said up thread he clearly sees you as beneath him - it's called contempt. That's why he thinks he's entitled to be waited on hand and foot when he's ill - and no doubt at other times as well - because he believes he's superior to you. Well, sod that for a start. If he won't relieve you now when you're so ill and someone has to keep caring for the actual children in the house, then you do the absolute bloody minimum you can possibly get away with for your kids and yourself. Anything else .... housework, ironing, and in particular, stuff for him can be left. So far as he's concerned I wouldn't lift another finger for him from now on - don't cook for him, don't do his laundry, don't tidy his stuff (if you really can't stand it chuck it all in a box under the stairs).
There's no way in the world he could have the kids taken from you - that's a nasty, empty threat from a pathetic abusive man trying to frighten you. Quite apart from anything do you really think this selfish lazy shit would have the first clue, or even want to care for them ? .... and how the heck would he cope with the school run then ? It's nonsense, and you really need to try and ignore that sort of crap.
As you say, with that attitude to women you don't want your daughters - or your sons for that matter - growing up and believing that's what they deserve or that's how they should behave (respectively). Please please when you're feeling better arm yourself with advice and info about separating (e.g. from CAB, Women's Aid, solicitor etc). You will feel ten times better without the weight of all his crap on you .... it's not easy being a single mum (was in that position for many years myself) but it's far easier - psychologically - looking after kids when you're ill and on your own, than looking after them when supposedly you're in a couple yet you're getting no help or support, because you're then having to deal with the emotional letdown as well as the practicalities.