I really feel for you.
There have been some really good suggestions. I really like the suggestion to prepare and freeze meals ahead. You asked about potatoes. I know home made are best, but while you are recuperating you might want to try some of the store-bought mashed (we have Bob Evans brand and a store brand in our local stores--refrigerator section, not frozen). Kind of expensive, but they are good in a pinch, and they are often on sale.
Also, if you belong to a church or club or any other kind of group, as someone mentioned, people might be happy to volunteer to help out. I know that when someone in our church has a problem such as that, people sign up to prepare a meal and bring it to them on their assigned day.
This will also be a chance for your kids to put their skills to work. I'm sure they would love to help out.
I sure hope you recover fast. But don't push it and try to use your right arm too soon or it could end up taking longer.