Also, there's no info on the repertoire; does it have any characters outside the x20-xff range?
Any actual dyslexics tried it?
Given the other comments on the thread that indicate that there are already free clones available, I'd say that it's probably reasonable for him to ask for compensation for his work and investment in tools.
It's in line with commercial font licensing.
You might also find this interesting: http://www.iansyst.co.uk/about-us/resources/directory/articl...
The slight deformity seems perhaps too subtle.
There are already alternate characters buried in the Unicode character space that could serve as simple substitutes, like ḏ or ḃ or ṗ.