Glad you will be able to visit. I am sure she will be happy to see you. These are such strange times. My sister and BiL in Sydney are in their mid 80's, still live in their own apartment. I always thought that if something happened to one of them, I could be there in 48 hours at the most. Now, because of my dual citizenship, I would be allowed to travel (if I could find a flight, there are a few) but would have to go into quarantine for 14 days on the way over and again on the way back.
They are discussing creating a Trans-Tasman bubble but I think it will be September at the earliest, some of the Australian states are not allowing people to visit from other states yet.
I first visited Scandinavia in 1974. I remember queueing at the German/Danish border. I had a campervan and an Australian guy asked if he could go through the border with me. He was on foot and they would not let him through. I told him I would drive him to Copenhagen AFTER he crossed the border but I was not going to take the risk that he might be carrying drugs. Never saw him again.
I also remember showing my passport at the Sweden/Norway border as the officer said "Ah Australia, capital Wellington" and I had to say No that is New Zealand, our capital is Canberra"
However I had to show my passport on the train from Oslo to Gothenburg in 2010 but not from Gothenburg to Copenhagen.
I took the ferry from Helsingor to Helsingborg, cannot remember if I had to show my passport there.
Until now, it has been much easier travelling in Europe this century than in the 1970's.