Yichud

Shalom, I am a yeshiva bachur currently staying at home. our house is only accessible to family members through a gate that can be opened with a remote. now i dont know what to do regarding yichud, its currently only me and my sister at home. leaving the gate open isn’t an option, but my father’s schedule is unpredictable since it depends on his clients. can i rely on that? or maybe since i know that when he leaves he won’t be returning for at least an hour or two does yichud apply during that time? no one else can enter unexpectedly, since no one else besides my father mother and brother has a remote for the gate and my brother never comes by during the day. am I correct that my mothers presence doesnt help, since there is yichud with two women, or is a mother different in this aspect? also, when the domestic helper (who is not Jewish) is present, can I rely on the presence of three people (my mother, sister, and helper), or does the fact that the helper is a goy not help in this case? Thank you very much for your time and guidance.

Shalom!

Thank you for your question.

There is no concern for yichud with a sister on a temporary, occasional basis.

However, if it is a half-sister please write back, since it would need to be further clarification.