Adderall for focus/energy

The great puzzle of dosage and meds. My husband has been on Provigil for about a year. He took 100mg morning, 100mg at lunch time but with little effect. I have asked Greg's neuro-onc to switch to Adderall, and she has. As of Sunday, Greg is now taking 10mg of Adderall XR. Some people in various blogs talk about a light switching on, increased energy and focus, I have yet to see much change. As background, Greg is 62 yr-old, with GBM, right frontal lobe, diagnosed May 1, 2015.  No resection possible. He has been taking the Stephen Western/Ben Williams cocktail since about October. Greg is now about to begin Avastin this Wednesday with the hope of reducing edema since nothing else seems to work and that includes cannabis oil, curcumin, etc. Sorry, two different subjects but possibly related?