Sometimes God places angels in your life to help you grow, He speaks through them, to enlighten you.
Sometimes when that period of disaster is over and you won’t need them anymore, God takes them away, and the distance between you and your angel grows.
Similarly, I hope I have been an angel in their lives too, though imperfect I was, I hoped God had used me in a way that still impacted their lives in a positive manner, that is still fruitful.
Some angels reunite after some time. Some don’t. Thank them for the experiences. Thank God for bringing them into your life.