I'm sorry for your devastating news. I hope i can give you some insight into this from your mothers perspective. I was diagnosed with cancer earlier this year and i can tell you that it is the hardest thing to go through. Cancer is a truly lonely illness and having to deal with your own mortality is confusing. Your mother has probably been through every emotion imaginable but without a doubt the worst is sadness thinking about the things she will leave behind. I am a father to three beautiful, funny, smart girls and thinking of leaving them breaks me. But despite all the sadness there is something else present, i no longer dwell on all the negative things that have happened. All the mistakes and family arguments just don't matter anymore.

Don't feel selfish, everything you are feeling is because you love your mother. The love you have for your mother is special thing and that will not go away or be any less special when your mother is gone.

Take care