I found it hard telling my loved ones about my diagnosis earlier this year especially my children. Whilst my primary school aged children have had information overload and thus are having their own struggles their councellor has told me that I did the best thing for them giving them too much information rather than not enough. Each of your children will respond differently, my 10 yr old wanted to go straight into councelling and get help immediately after being told of my diagnosis. My 6 yr old has only just started needing councelling now 6 months later. Both are happy go lucky children generally but when it comes to me they are both very clingy, my 6 yr old more so. As for my baby, he was just 6 months old when I was diagnosed so I'm hoping he won't suffer at all from the experience.
My reason for explaining all that ^^^^^^ to you is so that you & your hubby can monitor your children and be aware that all 4 of your children will react differently to the news. It may happen as soon as you speak to them or it may happen 6 or more months down the track.
Good luck with your surgery. From one mumma to another I wish you a speedy recovery so that you can spend more valuable time with your kids. xxx