I'm in exactly the same shoes. My dad got diagnosed with lung cancer 4th December and died 31st Decemeber after catching hospital borne pneumonia.  I'm trying to hold it together for mum but struggling myself. Would your mum want you to mope about for the rest of your life? I can just picture my dad telling me to 'Catch myself on and just bl**dy get on with it'  He was literally one of my best friends.   Your mum would want you to focus on your kids and give them as much attention as you can.  She clearly loved you and them.     Look after yourself.    And message if you want to chat.  Like you I'm hoping it all gets better than this because at the minute it feels like it cant get any worse.