the impeller seal went bad casueing his coolant to leak into is clutch cover and mixing with his tranny fluid.
as far as his head gasket it dosent sound blown his bike isnt smoking its got wet exhaust tips. meaning something isnt burning all the way off, so he either is running too much oil in his premix and it is saturating his packing , running to rich and all the gas isnt being burned , or if it is coolant it could be the head gaskets leaking or the base gaskets at the jugs and case letting collant past, or possibly a crank seal letting his tranny fluid into his motor. check your tranny level if its getting low that the case...