Two of our males bred our female in heat, will the litter be viable?

We breed Coton de Tulear puppies. We have the mother and father. We also have a boy from the first litter. The female is in heat. We were keeping the boy separated but mother and son locked last night. The sire has locked before and after. When the female and sire mate they usually do several times. Is the litter not viable? What do I do???