If a 1994 BMW 740il w 40L v8 Runs rough has thick anti-freeze smelling white exhaust and needs coolant refilled every two weeks or so is this a headgasket?

its most likely headdd gasket,, if compression check shows low compression then most likely,,, also couald be cracked head,, leaking coolant passages in intake manifold introducing coolant to heads,, pull plugs lookoing for coolant on plugs, if you find one or two adjacent with coolant on plugs then, bit the bullet, pull the heads and look for gasket or crack, buck