Question:
Is it Yichud for a 14 year old girl to sleep over night at her uncle’s house, when the only ones home are her uncle, his 7 year old son and 11 year old son?
Answer:
It is permitted. The reason being that during the day two men with one woman is permitted. At night though since people are sleeping, there is a need for one extra shomer, therefore three men and one woman is permitted.
Sources:
Rema E:H 22 -5.
