We don't really know for sure how old the dad is. It's not a detail that's focused on in the story. But if I had to take a stab at it, I'd say he could be in his mid to late 30s.
The 'a grand old tree story' could be about a very old tree in the forest. This tree might be home to many animals like birds and squirrels. It has stood there for a long time, through different seasons and weather changes. It could have a magical quality in the story, like being able to talk to those who are kind - hearted and listen to their secrets.
I'm not sure specifically as I haven't read it. But generally, it could be about the life of an old tree, perhaps its experiences over the years, the animals that live in it or around it, and its significance in the local environment.
Sadly, we can't tell who made the '91 whiskey fanfic'. It could have been a single individual with a creative idea related to '91 whiskey'. It might be someone who wanted to explore a story within a particular genre or setting related to this '91 whiskey' and decided to write a fanfic. There are so many possible creators out there in the world of fan - created content.
Well, without more context, it's hard to say exactly. '91 whiskey' might be a code or nickname in a particular fandom. Fanfic usually means it's a work of fiction created by a fan, so it could be about adventures, relationships, or any number of things involving this '91 whiskey' concept. It could be a story in a military - themed fandom if '91 whiskey' is a military reference.