There are two mountain busters. One right away after he does his big post heart explosion and the next one comes after the bombs/landslide phase so they are pretty easy to predict. Apart from that as a healer the only thing you need to remember are when the plumes come since everything else is easy to avoid without knowing it's coming. Plumes it helps to know so you can use sprint. It's best on Titan to not get too caught up in trying to remember every single detail or your mind focuses too much on that and not on healing.