Hi - so sorry to hear about your Dad and sorry  for any typos and it’s late at night! . In  our experience with my Dad the biopsy will determine the type of lung cancer (there are different types) and the other scans (CT and MRI) will look at where and how advanced things are. my Dad has small cell lung cancer which has spread to his brain (and that is very common with this type of lung cancer) It’s very frustrating waiting for answers tbh but in the mean time go to the official websites and they will help you to get a list of the questions you need to ask. Write down in advance anything you want to ask and don’t be worried about feeling under pressure to be in and out (.like a GP appointment!) In our experience you can wait a long time to see Consultants etc as the system is under pressure - not sure where you are but sometimes we have waited up to 2 hours to see the Consultant at our Oncology appointment so take things that will make the waiting time comfortable. As your Dad is still in hospital hopefully the CT/MRI will be being  arranged- just to let you know an MRI is the best way of determining what is happening in the brain- not a CT scan so push for the MRI.. My dad is 77 and after being very well after chemo and immunotherapy for about a year has deteriorated very quickly in the last week and is in Hospital and we are trying to get him home asap. I hope that sone of the above will help and support you and sending best wishes - you are not alone! (But sometimes it feels like that)