I read your post and it made me feel so sad. This is my opinion as someone who is suffering from terminal lung cancer. I would love nothing more but to see all my children prior to my deat. However not to the expence of one being stuck and maybe not being able to get back home. No I understand my children have there own lives, and I genuinely would not want them to travel from Australia knowing you were going to have a child, maybe not get back in time to see your child being born. Now I am pretty sure most parents would feel that way..... Although you say he's got a number of Brain lesions as anyone actually given him a prognosis, of how long he as left..... I would also disguss with your mum to ask his consultant if immunotherapy might help. Obviously it would be down to the consultant to decide if they thought it might help or not. If no prognosis as been given your mum should also ask how long. Have you set up soon of FaceTime calls. If so I personally think that's the way to go. With your dad being on a lot of morphine and suffering from depression. You could fly back to England to a situation that he's asleep due to morphine. Can you ask your mum if he's had a syringe driver fitted. It's a device that can have more than one lot of medication going into his body also how many he's actually already got he could be on two or more lots already if he as a syringe driver then I hate to have to say this but if he's being slightly or heavily sedated. You will fly back and you definitely would not be able to communicate with him because he will be knocked out for his own good. Because you dad may not be able to talk back to you. Either because it's induced morphine and antidepressant, I assum he's on. Or if he's on a syringe driver for his pain and sedation. No I am so so sorry but I honestly think you would be disappointed if you come back and find your dad is not able to communicate.  Go. With FaceTime or zoom something like that were you can see each other and say what you need to say to your dad. If he cannot communicate at least you can see him and say your goodbyes through that. Unfortunately you really would not have had a choice if we were still on lockdown. So all I can say no don't come back it does not mean to say you do not love your dad, I think if he thinks similar to myself he genuinely would not want you to come and then you being stuck without getting a flight back, I think he would be more understanding than you could imagine. He also would not be wanting you to feel guilty if everything seemed to be going so well why would he expect you to come back until. Things had settled down from coming out of lockdown. Even us in the U.K. are still not fully out of lockdown until 19/07/21 so please  say your goodbyes etc by zoom or FaceTime. Whichever is best for you. I hate to say this too. But how do you know your farther as not passed while your in mid flight. Yes it could happen. Cancer and prognosis is not a definite it's only based on figures that that been gathered over time. Not being a exact science cancer is evil and could decide to take anyone sooner than anticipated. Please please do not feel guilty however I would stay were you are, and I honestly think it's what your dad would want we as parents understand more than our children give us credit for. There's no way on earth I would want to put one of my children in your situation I would if capable be telling them not to come. We can communicate by FaceTime. I would prefer that than one of my children being stuck over here especially as your baby being due in August the mother and the baby need you more. Anyhow I hope everything goes ok.  But truly you dad does understand and wouldn't want you to get stuck over here. That I would put money on. Do the FaceTime etc ok marj