@Natascia that is a nice idea but both dogs would get stressed being boarded. They like human attention and the senior dachshund will not do well at all.
It would also be hard to schedule boarding and take them once labour's started i think. Better a sitter probably
If they don’t need to be home, you can look into boarding at places like JetPet (multiple locations in the city), they almost always have room except on major holidays and to be honest it’s nice to have the break from dog duties the first few days after delivery! We board our dog at Jet Pet North Vancouver for all our long distance family vacations and he loves it. Some other doggy daycare centers in the city also do boarding and can be flexible.