CE-525 First Officer reported a traffic conflict and a TCAS RA resulting in a go around; and a loss of aircraft control during the go around procedure. The First Officer as Pilot Monitoring identified the undesired aircraft state and provided verbal and flight control inputs to help the Captain recover the aircraft.

Narrative

I was Pilot Monitoring for my Captain today. We were flying from ZZZ1 to ZZZ. While on a very short right base for Runway XXL we were far too high to make a stable approach. However; my Captain chose to proceed. He did not accomplish checklists and over sped the flaps trying to get low enough to land. While this was happening; I was trying to monitor and accomplish checklists. ATC then called and advised there was traffic for the parallel XXR. I replied with 'looking; Aircraft X'. Shortly after the Captain drifted right of centerline. I did not have visual with the traffic. We immediately got a Resolution Advisory. At this point we were maybe 300 ft AGL. I commanded to go around and comply with the RA. Captain refused saying he 'could still land'. I commanded again and told ZZZ Tower 'Aircraft X going around. We got an RA'. Captain then said he could save the landing again. I said 'it's too late I told ATC He then screamed 'expletive' at me and began going around. The event directly following the go around nearly resulted in a stall spin very near the ground. ATC gave us a heading which Captain proceeded to miss by about 90 degrees. I called this out to Captain multiple times. He turned back for the heading and brought the thrust to idle. Very shortly after Captain lost control of the aircraft as we were nose up; rapidly decaying airspeed (lowest was 110kts); thrust idle; and about 60 degrees of bank. I called these issues out multiple times until I pushed the thrust up and nose down. Following my action Captain regained control. I have let my company's Director of Operations know about the full situation."