Caring for kids with a broken arm?

[appletree]

Df who is currently a sahd broke his arm at soccer yesterday. He is having surgery this morning and I am wondering how he is going to go looking after our 4yo dd and our 1yo ds? Is there anything he won't be able to do? Will he get used to doing things with the cast on? This is the absolute worst time as I have next to no leave yet, my colleague has just gone on holidays so I can't afford to take time off even if I had it, and my boss is completely stressing out with all of the work we have on at the moment.

Any tips or advice for how I can help him? I am going to go to work really early so I can get home to make dinner, or else chop everything up in the morning so he can throw it all in when ready. I think his mum may come to help him the first few days, but I can't guarantee it as they are the type to offer lots of help but never follow through when we actually need it.