First, I'm sorry your son is struggling right now. You are doing well to connect him with resources.

As to ADHD: yes, it is possible to have an ADHD profile, yet not have apparent challenges in school. However, given your description of his historical presentation, I am more inclined to attribute the current difficulties with focus to depression or other emotional factors, as it is well known that children and adolescents quite often present as inattentive when under emotional distress (actually, adults do too). Given that the psych also diagnosis depression, I would be exceptionally cautious about medicine--stimulant medications, which are often prescribed for attention deficit, can have serious and even dangerous side effects in persons with depression. I would strongly suggest that any treatment (medicine or talk therapy) addresses the depression first. If there were still ADHD symptoms after that, further consideration of ADHD would be better supported.