My ds was diagnosed when he was 5 as being dyslexic.
Last year he started at a new school which happens to be CRESTd (ie the dyslexia association have it down as a good school for being dyslexic), I gave them a copy of the Ed Psych's report which showed he was highly intelligent but dyslexic.
The school LSU said he is average intelligence and not dyslexic when they tested him, and the reason for the difference was because when the report was done he was too young.
My ds plays the piano. I have noticed that he cannot recall the pattern in a piece, ie if he plays four bars then plays four different bars and then the third set of four bars are identical to the first set he cannot see that at all, therefore he has to learn the second set of bars over as if for the first time like the first set.
I am unsure if there is anything that I can do to help him, as school give him no additional support and I know he struggles with this in other areas such as maths he doesn't see sequences.