Hi Kevin,
I am so sorry for your loss. It sounds as if the male attacked her for some reason. This is unusual, as the females are the ones who tend to be aggressive. And males are more likely to attack a young female because he wants to breed and she isn’t ready. But at 2, she was certainly old enough to breed. It’s also unusual for something like this to happen at night, since they have very poor night vision. Was it the type bird bath they go inside of? Could she have gotten stuck and he was trying to free her? It’s also possible that something was wrong with her and she died and he was trying to revive her – I have seen this often with budgies. I know this doesn’t change anything, but it can help to know what happened. The male will grieve, but should be OK. If you decide to get him another mate, you will need to try to find an older female. It isn’t safe to put a female under 2 years old with a mature male. Again, I’m sorry this happened.
Take care,
Brenda