For fonts, we need the Windows font name, size in pixels or points, and Unicode range required. Per Wikipedia: ISCII uses 8-bit code which is an extension of the 7-bit ASCII code containing the basic alphabet necessary for the ten Indian scripts which have originated from the Brahmi script. There are 15 officially recognized languages in India. Apart from Perso-Arabic scripts, all the other ten scripts used for Indian languages have evolved from ancient Brahmi and have a similar phonetic structure, making a common character set possible. The ISCII Code table is a superset of all the characters required in the Brahmi based Indian scripts. For convenience, we use the alphabet of the official script Devanagari we can provide downloadable fonts accessed as 8-bit characters if you can provide a font with ISCII characters.
See Fonts for Embedded Touch Screen Development for a comprehensive explanation of working with fonts.