It’s so dystopian in the states. When I needed Ritalin I spoke to my GP, they referred me to a psych. Did three sessions and then the psych called my doc and asked him to write a script.

I was high on cannabis 24/7 for 20 years. He is going through withdrawal and it’s going to be tough for the first month. After that he will start sleeping better but still have really vivid dreams. Expect a short temper and irritability. Months 2,3 and 4 won’t be that bad. If he has anxiety issues like PTSD then just be prepared for the chance that stimulants will adversely affect that. Long term cannabis use also can cause anxiety. Good luck finding what works.