Is it difficult to receive and to give recognition? Is it even more difficult to give the necessary feedback when behaviour and performance need to be corrected.
To receive recognition and feedback about what we do is a basic condition for our well-being and for making us do a good job. Even with a big ego and lots of self-confidence you need to know what the situation is like, whether the efforts have any effect and whether it is satisfying.
Try it! Perhaps all that is needed for your colleague to recover his balance and get back on track is that slight extra attention and recognition.