I’m assuming you mean to ask if your hair, after brushing dreads out, will be healthy or not.
The answer is that it can be very healthy! You have to take good care of your locks while you have them- moisturize as is appropriate for your hair texture (for the curliest/kinkiest hair, this may mean regular cowashes and adding oil, while for those with straight hair this could mean conditioning once every 1-3 months).
As you remove your locks, be gentle. Do not brush out fully wet locks. For some, having the slightest damp hair may help, but remember that wet hair is weaker than dry hair and may break easily. Do not rip a comb through your locks- take your time and gently untangle them. Better tools than a comb are shown in this video: http://www.youtube.com/watch?v=cwXca0xN31I
But the short answer is that yes, you can have very healthy hair after you remove your locks. You may cause minimal damage creating them and maintaining them, but otherwise it will be lovely and healthy hair. I’ve put in and removed locks several times and every time my hair was healthy underneath. 🙂