Our older female dog has just come into heat, we have recently got a puppy who is now 5 months old, and he has been getting pretty friendly with her since she's been in heat.

Can he get her pregnant, his testicles have not dropped yet, is that a good sign, we can't get her spayed as she has a weak heart, we are planning on getting him fixed soon, as we don't want any unwanted puppies, and plus the way her heart is she probably won't make it through giving birth to puppies anyway.

So please any advice would be great