it is only the first week you have to worry about, getting over the surgery, then you will work out the best way to do things. There are women who only have one arm who manage to cook and look after their kids. even with plaster on you will be able to use the arm somewhat and will be fine.

Stock the freezer with easy to do meals, the kids love fruit and sandwiches for lunch, the lawn can go a bit feral if you or DP can't do it. The girls can take a term off swimming if it is too hard with the cast, although if the op isn't until next year DD2 will be able to go in the water by herself anyway, and you just have to get them dressed.

Don't put the op off again if it can give you big benefits, over little things that can be worked out now.