Does allowing a guard dog into the house for a short period lead to the loss of a qirat of good deeds, even if its primary function is guarding?

It is forbidden to keep dogs except for hunting, guarding livestock, or crops. It is permissible to keep them for guarding homes when necessary, by analogy. Keeping a dog for reasons other than these diminishes the owner's reward by one or two Qirats daily, and also prevents angels from entering the house. This applies specifically to dogs whose keeping is forbidden. One must be careful of the dog's severe impurity. Your sister should place the dog outside the house and you should advise her not to play with it so that its saliva does not touch her, leading to difficulty in purification.