pregnant queen and our other cat

hi all ths is my first time posting we have a pregant queen and an older male cat (spayed) they get along fine but sometimes are a little ott with the playing anyway i kow when her time comes shewill be separated from our older cat but was wondering when was the last possible minute i could do this? could she birth first then i shut her off where she is or is there a risk he could go in there and kill or mame her or her babies? thanks

I leave my girls in with other cats until a few days before her due date. Your boy shouldn't harm the kitten, but she might lash out at him protecting her babies, you just never know.

I have neuters along with my breeding cats and have never had an issue, though I keep the mums in their own room with limited or no visits from other cats. I have one boy who likes to meet new arrivals, if the girls allow he grooms the mum and smells the kittens then leaves.
The kittens interact (under supervision) with the other cats once they reach 8-10 weeks.

thanks for the reply in your opinion would his boisterous nature with our queen (they have always been this way she is as equally bad as he is) reflect on how he will behave with the kittens? they are a very close pair he is 3 and she is 1 1/2 he is a rescue cat and was used to being around other cats and got our little girl to keep him company when they first met we had a few teething problems for a few days but it was mostly him asserting himself now they get on like a house on fire they are still sharing sleeping quaters and he is still grooming her etc but i am a little concerned he may try and assert domanance over the kittens when they are only a few days weeks old could he see the kittens as a threat?

thanks