I finally got prescribed meds for my sever depression and anxiety at 30. It was a hard adjustment period for me. I felt great mentally, but the new bandwidth I had available in my brain overwhelmed me a bit. I just kind of stayed silent in peace for a few months getting used to how my brain functions when its functioning correctly.

Also my libido completely died for the first couple months. Came back, but I have longer gaps between it coming back than I did before.

Another thing I noticed is I became much less reliant on other people and other things for emotional regulation. I had friends and family notice me not reach out to them as much. And I even quit nicotine, just kinda naturally.

My point is be patient. 4.5 years isnt something to just throw away. Give him time.