> What do you all think - is this a healthy way or not?

Have him get a bodyfat test every month or so.  If he continues to lose
weight this will alert him to how much of it is fat and how much is muscle.
The scale won't do that.  Losing muscle is a sure sign he will rebound and
regain the weight.  If he maintains the muscle then he has a greater chance
of success.

mas