Hopefully, he is on the way to the workshop to settle this issue. White smoke in such instances means there is a serious problem with the engine.
Excessive White Smoke From Exhaust
One of the main causes of white exhaust smoke and is a cracked or warped cylinder head, a cracked engine block, or a blown head gasket caused by overheating. A cracked head may allow coolant to leak into one or more cylinders or into the combustion chamber of the engine.
It’s important that you do not ignore thick white smoke coming out from the exhaust – even if it’s only a small crack in your engine, the damage can easily become more extensive and this can lead to the engine breaking down completely and having to be replaced.