My dads male bullmastiff keeps whimpering during day & howling at night?? Am thinkn its my dog in heat?

Ok so I recently moved in w my dad and I brang my pomeranian girl and my chihuahua boy. So my pom pom is in heat (shes a teacup :)) and I leave my doggies outside during most of the day in the backyard.. My dads bullsmastiffs have their own pen..but I noticed that da male mastiff whimpers when my girl dog abby isnt around and at night he howls.. (they sleep inside) hes howling at the moment ughh! Is this bcuz shes in heat n he 'wants her' bcuz I kno dogs can smell girl dogs during their period n stuff.