I suspect that huge amounts of practice to improve his writing may create much misery, but have limited effect, especially in the longer term. Dysgraphia doesn't fix easily, but it's readily by-passsed with a keyboard.
I'd second this - with the exception that if it is dysgraphia, chances are it won't "fix" at all. Handwriting might look neater with time, but the challenge with dysgraphia that's not easy to see is the impact on written expression - the dysgraphic person has to use a significant portion of their working memory forming letters which in most people is instead free to focus on spelling, punctuation, grammar and most importantly, content.
One other note - if it is dysgraphia, then he doesn't need to develop lightning-fast typing speed for typing to make a difference. Let him develop his own method of adaptive typing and don't focus on the speed.
Best wishes,
polarbear
