To a point, yes it can be repaired. And that repair may be good and last. But that depends on a lot of things, such as why did it fail in the first place? It could be the foundation or lack of a footer that can carry the fireplace. In which case then no, you can’t really repair that without a rebuild. Fireplaces have a skeleton called a chase as well. If the chase it at fault then it may not be possible to fix without taking the facing off, which would essentially be a rebuild. Typically when some one “repairs” masonry it’s not an actual repair, it’s a re-point. Which is, in the case of a failed chase or footer, basically a bandaid on a gunshot wound. You may not see as much blood, you it’s still bleeding internally and the bullet is still lodged in there somewhere. But again, it could have just been because of a thousand different things and be fine. But bowed walls with cracked fireplaces sitting on top of them is a scary prospect.