Should my sister and I pray individually or in congregation?

Congregational prayer is obligatory for adult men, and it is best performed in the mosque. A Muslim may pray in congregation with his sister if he is unable to go to the mosque, because a congregation is formed by two or more people, even if the imam and the follower are a woman or a slave, with the exception of Friday and Eid prayers. It is also permissible to perform it at home or in the desert. It is better for your sister to pray with you in congregation, to attain the virtue of congregational prayer, which is twenty-seven degrees, even though it is not obligatory for her.