Childhood leukaemia

My 3 year old grandson has just been diagnosed with type B Acute Myeloid Leukaemia. He is going to be treated at the Sutton Royal Marsden, being transferred there tomorrow from another hospital. I realise that this is the most common form of the illness with a very good recovery rate, this is backed up by plenty of internet research. But I’m still desperately worried and would welcome advice, information and other help - SPECIFICALLY from people who have a close preferably family connection with a child who has been through this traumatic time recently.
Thank you