Hi Debilitating (Megan N), and thanks for your post and question. The answer is yes - you can interact with the communities separately. If you delete your Facebook account, you will still be able to sign on, access, and interact right here, in our COPD.net community, just as you do now.
I hope this brief response addresses your concern.
Wishing you well,
Leon (site moderator COPD.net)