[Help] How much time should I keep my dogs apart when the female is in heat?

I have two dogs, a female Pinscher and a male Dachshund. The Pinscher is in heat, the Dachshund obviously became crazy as soon as she entered the first cycle, and everything just got worse when she started accepting him. My SO and I decided to separate them, even went as far as hiring a nanny to take care of the male for a week.

By now, the female has been in heat at least for 11 days. The male returned home since we can't afford more days with the nanny, but he's still like crazy. He doesn't want to eat, or sleep much, and he's sniffing everything all the time and crying on the bedroom door. We are keeping them apart in the apartment, because the female wants to bite him every time he comes near her.

I don't know what to do. It's not unfair that the male suffers so much, but the female is not guilty because she's in heat.

How much time do we have to keep them apart? Is his behavior normal? What can we do to make it better until this stops?

I heard that if the female drinks a bit of chlorofyll, the scent of the pheromones will be a less strong. Is this true? If so, how much should we put in her water?

We need help!

Edit: We know that they must be spayed/neutered, however, they aren't because of different reasons (they were living in separate houses, we moved countries and now they are forced to live together, and moving countries in a sort of refugee situation means not having money right away to pay for that type of proceedure. We were planning on doing it, and saving for it, but everything happened way earlier than we expected, hence the issues.