Advice for Berlin lodging

The Hackeschermarkt area is on the major e-w local train line and just across the river from the Museum Island (Museuminsel). Google's AI says there are 80 Christmas Markets in the Berlin area so you can probably find one or more of interest anywhere. But...the Gendarmenmarkt is just west (6-8 blocks) of the Museum Island.

https://www.weihnachtsmarkt-berlin.de

Hackesher Markt is a good area with public transportation nearby and numerous restaurants.

I've stayed at the Adina Hotel at Hackescher Markt a couple of times. Others on this forum have as well.

Each room has a small kitchen and some even have washers and dryers in the room.

I also liked the Adina at Hackeschermarkt, for the room and the location. It's about a block from the S-Bahn and the tram, and a few blocks to the U-Bahn. It's walking distance for most people from Museum Island, Unter den Linden, the Brandenburg Gate and the Reichstag building, but maybe not for your parents. I haven't been there at Christmas but I expect the Hackeschermarkt is a lively scene then.

There are more hotels in central Berlin, including large chains, that might work better for limited walkers. Looking at Google Maps, I see the Westin Grand and NH Berlin Mitte along Friedrichstrasse, both close to U-Bahn and S-Bahn and more walkable to the central sights. I don't know those hotels but I'd assume that a Westin or NH would be more than adequate.

Berlin transit is very good. If you get a pass for the length of your stay, you can just walk in and out of the stations and trains, no turnstiles, and I think there were elevators or escalators wherever I went. The pass or ticket is subject to inspection on the train.

I like the Hotel Melia, Friedrichstr., special the categorie „The Level Room“. Loved the breaks in the Lounge. Cafe, Drinks, Snacks incl..

Walking distance or short ride to the Brandenburger Tor. The famous Hotel Adlon. Friedrichstadtpalast with great Show Revue, nearby.

If you like to stay Ku‘Damm I‘m voting for Lindner Hotel.

I loved the Adina Hotel Hackerscher Markt. Close to transit and museum island plus a kitchenette where you can make simple meals. And the 1bdrm has a washer/dryer. The location can’t be beat. My room looked out to the TV tower.

Here's another vote for the Adina Apartment Hotel Hackescher Markt. It's a great hotel with good service, very comfortable rooms, and a lot of amenities. And I love the Hackescher Markt location. It's very near lots of public transportation. In fact, you can even take the S-Bahn directly from the airport to the stop that's about a block from the hotel. It's within a short walking distance of the DDR Museum, the Fernseher tower, and a little bit farther is Museum Island and Unter den Linden.

There are loads of restaurants and cafes in the area, several grocery stores, and a couple of wine shops. It's really a wonderful place to stay, and I would definitely stay there again. https://adinahotels.com/en/apartments/berlin-hackescher-markt/

We stayed at the Adina Apartment Hotel Hackescher Markt in May, I agree with everyone about what a great place it is. Every member of the staff that we encountered went out of their way to be helpful. We ate all of our evening meals outside at various restaurants at the Hackescher Markt.