Answered by Shaykh Sohail Hanif, SunniPath Academy Teacher
Today I was praying zohar namaz (farz rakat) by myself. And another brother just joined me while I was praying. He stood behind me and just followed me as if I were an imam in a 2 man jamat. I do know that if 2 people are already in a jamat and praying then a 3rd and so on can join them, but I don’t know if it is allowed for a brother to join another brother who is praying by himself. Is this permissible?

Assalamu alaykum
It is not a condition for the imam to intend being the imam for the prayer of the follower to be valid. The follower’s prayer is valid as long as the imam was praying the same prayer as him if the follower intends a fard or wajib prayer. [Radd al-Muhtar, 1:284, Dar Li Ihya al-Turath al-Arabi]