Ralf Schumacher accused his elder brother Michael of dangerous driving that could have broken his neck after a last lap incident in Sunday's Monaco Grand Prix.
Michael, the seven times world champion, tried to overtake Ralf's Toyota on the final lap and their wheels appeared to touch at high speed. Ralf held on for sixth place as Ferrari's winless streak stretched to seven races.
"That was very dangerous," Ralf told German television after the race. "Sometimes Michael isn't all there. Sometimes I have the impression he turns his brain off."
Ralf told Monday's Bild newspaper: "If the tyres of either of us had shifted slightly, they would have been off (the track).
"Then he would at least have broken his neck. Personally I don't want that."
Michael was unmoved by Ralf's criticism.
"I was only six-hundredths of a second behind Ralf and my attack was perfectly acceptable.
"I am a full-blooded racer. We're not on a Sunday outing."