Sorry to say that I don't know any of his siblings' names. Michael's death cert. states that his parents were Roger TIERNEY, a farmer, and Catherine KILLEEN that he was 74 years old [in May 1873], and was a native of Galway, Ireland. His immigration record to NSW has the same details for parents, and that he was from Dunmore in Galway.
Without knowing how common the names TIERNEY and CONNOLLY were in Galway, it sounds to me like a likely connection! What year did Patrick marry Margaret?