It sounds to me like Direct Instruction is a particular brand of curriculum rather than a method. Dyslexics do benefit from explicit, systematic instruction, particularly in phonemic awareness and phonics. The book recommendation has been made here (sorry I don't remember by who)
The Mislabeled Child by Eide & Eide which addresses "stealth dyslexia" or see
http://mislabeledchild.com/html/Library/DyslexiaReading/Stealth_dyslexia.htm. I would also recommended
Misdiagnosis and Dual Diagnoses of Gifted Children and Adults. Also see the
International Dyslexia Association for a list of Orton-Gillingham influenced and other multisensory programs which have been extensively researched and are recommended for people with dyslexia.
Hope this helps!
