Male Franciscans are called friars, which comes from the Latin word meaning "brother", because St. Francis intended his followers to live as brothers without distinction of rank, title, or education. Friars live in communities called fraternities and the house they live in is called a friary. In addition, Franciscan friars are one of four mendicant orders whose lifestyle is itinerant, rather than committed to living in a specific monastery for their whole lives.
All Franciscans are formed in their vocations in the same way, they follow the same schedule, wear the same habit, make the same vows, follow the same Rule, and have the same leaders, starting from the General Minister in Rome, the provincial minister in the local area to the guardian who ministers to those who live in a single friary. A Franciscan’s day is composed of prayer, time with the community and work. As the friars go through their formation, they discern what kind of ministry they have the ability/interest in pursuing. It is at this point where training/education can become more specialized depending on whether they are called to sacramental ministry (priesthood) or any other ministry which is aligned with Gospel values and serves the people of God.
Since you cannot be sure if a Franciscan friar is a priest or a brother, addressing him as brother is never wrong.