I believe Ellie it would be the Lord's will for you to encourage others in the Local church to live for God,and if your brother or sister is in error, especially if you have built a relationship with them, why not tell them!? Thats all im saying..i wish somebody would have taken the concern to tell me when I was slipping into error..i did not have that even when I sought accountability with many pleas and tears. And those same ones i asked made excuses as to why they were silent and irresponsible brethren(my assumption is they were hoping id join their church and then and only then would they be accountable to me) or worse off, remained silent and looked the other way.
But having said that, this is merely an encouragement to not look the other way..if this provoked a temptation for you to respond in the flesh, i pray that you see what i say is not a jab at you or anyone, but merely an admonition out of a conviction and out of personal experience..wishing I myself had this in my life in the past..i couldn't find it even when i literally begged for accountability..now years later, i found christians that are available,and bold enough to address what needs to be addressed. That is all neighbor.