As concerned believers we are to look out for each other, not just Number One, and that includes being interested in each other's affairs and business and/or family dealings. We are to mind our own business, though, when appropriate and not to become busybodies, snooping into affairs where we are not welcome. It is tempting to become aloof and not care about the everyday, mundane lives of our circle of friends and sphere of influence. Peter says that no believer should suffer as a busybody in other's matters, where we are intruding and unwelcome--the key is to show interest, not being "nosey," or prying! Some people are encouraged just to be assured that we care and this is a methodology to preach the gospel. We walk the straight and narrow path to balance the two extremes of ignoring them and meddling.
Paul warns about people who don't work, but expect others to support them while they become busybodies (cf. 2 Thess. 3:11). We are told expressly to mind our own business in 1 Thess. 4:11, NKJV, boldface mine, and I quote: "... [A]spire to lead a quiet life, to mind your own business, and to work with your own hands, as we commanded you." We must seek an open door and seize the day (carpe diem, in Latin) when we see opportunity knocking where we can lend a helping hand--for Christ has no hands to help with but ours!
Some believers are naturally charismatic and gifted to handle private matters and to extend mercy and help to those in need in the body. The primary cause of intrusion into the matters of other believers is lack of productive lives, where one has too much free time or downtime; the saying goes: "An idle hand is the devil's workshop." Note that Ecclesiastes 9:10 says that whatever we "find to do," do it with "all our might," and we are not made for idleness, but for work to suit our image of God and find fulfillment and meaning.
In matters of others, we are to demonstrate the love of the brethren and how we can extend it to all in need within the body of believers. Some folks believe religion is a personal matter and one should privatize it and not interfere. One reminder: don't get personal, without permission, the go-ahead, or the green light you cannot guarantee the outcome or final result--the Holy Spirit has the job of wooing and prompting the person's interest to open the door. As a final caveat: Never pry into uncharted territory where you aren't welcome--build a relationship first and earn the right to get personal! Soli Deo Gloria!