Hoping someone can help me.  My son really likes the Wings of Fire series of books, there are for middle grade kids.  He has aged out of them and I want to get something similar for high school grades (he’s a freshman).  He reads at a much higher grade level but, at the same time, I don’t want anything inappropriate for a 14 year old.  Thanks!

https://www.literature-map.com/tui+t.+sutherland suggests books by Erin Hunter. According to Wikipedia, Erin Hunter is a collective pseudonym used by the authors Victoria Holmes, Kate Cary, Cherith Baldry, Inbali Iserles, Tui T. Sutherland, Kasey Widhalm and Rosie Best, in the writing of several juvenile fantasy novel series, which focus on animals and their adventures.

Literature-map.com is a great way to find similar type authors. You'd have to check on the appropriateness though of anything you found.

Thank you, I’ll check it out!

The Last Dragon Series by Chris D'Lacey.  The first book in the series is Fire Within.