I just looked at my 3.6 installation of CA PM and eHealth is listed as a choice for adding as a data source. So, _IF_ it still works, which it may not any more... to register a distributed eHealth cluster as a data source you have to connect it to your reporting front end console for the eHealth cluster. You can only do one, and it has to be a RFE console system.
One thing to note... if your eHealth RFE is already registered to another CA PC or NPC, you will have to unregister it from the other one before you can register it to your new CA PC since it can also only be registered to one PC instance at a time.
You can always try it and see. I'm trying to move off of eHealth officially now (even though my "cold dead hands" are resisting futilely!) and I was not planning to connect it to my new CA PC. But if my current issues persist I may have to reconsider doing that.
Let us know if it works for you.
Chris