Does Fitz return to normal?

Eventually, Fitz was reunited with his team after traveling between timelines through the Quantum Realm, and took part in the final victory against Sibyl. He and Simmons then retired from S.H.I.E.L.D. so they could raise their daughter and live a peaceful life.

Does Fitz ever recover from brain damage?

In the aftermath of the Season 1 finale, fans find out what happened to Fitz. After Nick Fury (Samuel L. Jackson) rescued Fitz-Simmons, the Scottish scientist was in a coma for 9 days. Months into the recovery showed Fitz was still healing from the incident as the oxygen deprivation had caused brain damage.