小狗(男)絕育後還有冇性能力和性需要呢?

I have 2 chihuahua, 1 boy & 1 girl.
We brought the boy first and brought the girl 1 year after, so the boy is 2 years old and the gal is 1 now.
The boy has been desex when the gal arrive.

Now my gal is in her second 發情期
They try to have sex these few days, the gal didn't resist and I am not sure if the boy chihuahua can still erect
They didn't have the humping act before at all!
So can he still perform sex???
Or should I leave them to that? Any advise? Thanks!