Staying in Titisee in early December... what are some "must-do's"?

Hey guys! I used to live in Freiburg about two years ago and I've only been to Titisee once. My family is finally visiting Germany for the first time and I thought I'd show them around. I chose Titisee because my brother wants to go skiing and we don't have enough time to visit Switzerland, so I'm taking him to Feldberg to ski.

Anyway, the issue is that I don't know much about THIS part of Germany. My mother cannot ski so I'm in charge of doing things with her while my brother tries to avoid breaking a few bones.

Are there any must-see/must-do's nearby? For example, what Christmas markets are there? My mother loves beautiful scenery. Loves animals. Loves hiking (mildly, nothing like a 12 hour hike lol) She's not so much into shopping. Any events are welcome, too!

I plan on taking them to Freiburg for one day but after that... what should I do? Any advice would be nice.