Srila Prabhupada and Srila Sridhar Swami were Godbrothers. Here is a small conversation, hinting their relationship…
Prabhupada: So we are thinking we are very much fortunate to hear His Divine Grace Om Visnupada Paramahamsa Parivrajakacarya Bhakti Raksaka Sridhara Maharaja. He is, by age and experience, in both ways he is senior to me. I am also always fortunate to have his association for a very long timeperhaps since nineteen hundred and thirty or something like that. At that time, he did not accept sannyasa; he just left home, vanaprastha. In his white dress he went to Allahabad. (Aside, to Sridhara Maharaja:) Maharaja, I think you remember this incident when you went to Allahabad.
Sridhara Maharaja: Yes, I do.
Prabhupada: Yes, thank you. Yes, at that time…
Sridhara Maharaja: We took prasädam on the roof…….
>>> Ref. VedaBase => Room Conversation — March 17, 1973, Mäyäpur