The bulletin of the combined parishes says that Mass is offered Monday to Friday at the convent of the Missionaries of Charity, 34 Aberdeen Street, telephone 718-443-2868. Sunday at 11 a.m. a bi-lingual Mass is offered at 89 Furman Avenue.
For an excellent capsule history of the parish, please see McNamara's Blog, linked here. The parish of St. Francis de Sales was established in 1872 and renamed Our Lady of Lourdes in 1897. For many decades, it was staffed by the Fathers of Mercy, a missionary and preaching congregation. That may be one reason for the the large size of the rectory.