I'm sorry to hear you dog lost his buddy.

I'd introduce the pups slowly, see how the male responds to the female. Pay attention to your male, he should let you know if he's not interested in making friends.

I'd have them both on a leash and introduce them outside on neutral territory. If your male drops his front legs on the ground with his ass in the air, that's good! If he stiffens up and lunges that's not good!

Good luck, let us know how it goes!

S_B