I like what Riley and Nekhbet wrote.
Take both dogs to a vet. I've also encountered times where a younger dog will attack an older dog - for no apparent reason, but it ends up being a struggle to the death. So please keep them separated and keep the female dog on lead if she's in the same space as the male dog.
Dogs are not always great at deciding what's in their own best interests - so you have to do it for them. The male dog should get over being separated, hopefully the behaviourists can give you some strategies for managing.