Unless the Brill class file is under active development there won't be any official release to CTAN.
Authors of the series have access to a private TeX Live repository.
All others please use the TDS file to install the files to your local TEXMF tree or just copy all files in your working directory.
ustring library
- Fonts https://brill.com/page/BrillFont/brill-typeface https://github.com/googlefonts/noto-fonts/tree/bc9353da6f625b7a47035de952c2e8fd9e3ae889 NotoNaskhArabic-Bold.ttf NotoNaskhArabic-Regular.ttf NotoSansAvestan-Regular.ttf NotoSerifDevanagari-Bold.ttf NotoSerifDevanagari-Regular.ttf NotoSerifGujarati-Regular.ttf NotoSerifGujarati-Bold.ttf
KHUSRO__.TTF http://minerva.stkate.edu/offices/academic/classics.nsf/pages/pahlavifonts