She can try out Pencil 2D, TupiTube, OpenToonz, Animation Paper or Synfig. All are free. However, none of them will hold your hand and teach you the principles and craft of animating. To do that, you should buy her:
https://www.amazon.com/Cartoon-Animation-Preston-Blair-techniques/dp/1633228908/
And
https://www.amazon.com/Animators-Survival-Kit-Principles-Classical/dp/086547897X
I'm not sure if you want to be an animator or not, but there are lots of good places to start. Cartoon Animation by Preston Blair is a great place to start. He has a classic old school look but his drawings are just so full of life and energy. He animated Mickey Mouse in the Sorcerer's Apprentice section of Fantasia and also worked with Tex Avery at MGM.
Most animators seem to rely heavily on the book The Animator's Survival Kit and also hold in high esteem the older book about the Disney process, The Illusion of Life. The former book is highly technical so it might not be directly applicable unless you're actually trying to produce an animated short. The latter book is not an instruction book per se, but contains loads of information about acting, animation, and production. You might also look into the Walt Stanchfield lectures, which have been collected into two volumes called Drawn to Life. Walt was the life drawing teacher at Disney and his lessons are among the best, even for non-animators.
For online courses, Aaron Blaise has lots of online lessons at creatureartteacher.com, which are worth looking into. NMA.art also just released an animator's intro course. I'm sure there's also good animator and character design content over at 21-draw.com.
For character design, Tom Bancroft has a pair of books, Creating Characters with Personality and Character Mentor, that are very good and nicely structured around learning things like shape design, personality, color, staging, etc. Stephen Silver's character design book, The Silver Way, is a good alternative if you're looking for something a little more stylized -- like the Nickelodeon and Cartoon Network shows. Though they're not quite as good at structured learning, you can also learn a lot about character from Ben Caldwell's two cartooning books, Action Cartooning and Fantasy Cartooning.
All of this assumes you already have a decent grasp of the basic drawing skills. If you still need to develop those, DrawABox.com, Loomis's Fun with a Pencil, or any basic drawing course should help you get more familiar with the tools and techniques. Be warned that most courses in this area are going to ignore the crucial step of mark making, and most self taught artists struggle a lot with this skill and don't even know it. Unless your course is teaching you how to hold a pencil and how to draw from the shoulder, you're skipping steps that will continue to hold you back.
The trick though is not to get bogged down in the research and preparation phase and let that become an impediment to putting in the work. You don't need all these books to get started. Pick one or two that you think you are most curious about and just start there.
Totally doable. Many paths in 3D. I know a bit about tv and film. But games should not be ignored. That said this isn’t my area. But get on a path asap.
Don’t know a ton but I heard a few good things about animationmentor.com
If that’s not a fit that’s fine. Fine something to get out out of tutorial hell asap. A structured program of some sort helps.
There’s good online classes. See if you can loosely follow a track.
https://www.cgmasteracademy.com/courses/animation/
If you can’t afford a whole semester of this stuff, take one course every few months. Every term at least one. And keep at it. That’s what i did.
I don’t know your starting point, but I actually would do at least 1 drawing course. Something to get you started. Do a ball bounce and basic animation. This is a very good fundamentals book for both posing and animation basics. Not a lot of pages, very to the point. (This is regarding posing for drawings, but in 3D you still pose and design good angles and silhouettes)
Cartoon Animation with Preston Blair, Revised Edition!: Learn techniques for drawing and animating cartoon characters (Collector's Series) https://www.amazon.com/dp/1633228908/ref=cm_sw_r_cp_api_i_VJS3HF7S722NRQEQ1VXK
Drawing and animating are separate skills and there are a lot of resources out there (paid and free) to learn them. Youtube and twitter has a lot of stuff you can pull from. (search: 'how to animate', 'how to draw', etc)
In terms of drawing, it helps to get the fundamentals down first. How to look at objects, composition, objects in space, etc. Then look at the artists/styles you like and study them to determine what direction you want to go in. I've recently been looking a lot at the Etherington Brothers twitter account and there's been some good stuff posted there.
For animation, a couple books that some swear by are Animation by Preston Blair and The Animator's Survival Kit by Richard Williams.
All of the flashy stuff you see in anime can be broken down and explained with the ideas presented in those books. They aren't the only resources but they pack A LOT of information. It also helps to study animation that you like frame-by-frame to see why and how something moves the way it does and why it does or doesn't work.
Like any other skill/discipline, these things take practice and time to get 'good' at. So don't get discouraged if you don't learn what you want to learn in a couple days (or even a couple years).