I would say, "Thanks for the concern, I appreciate it." I would then say," Remember that scripture about being " spiritually " sick?? What does it actually say? Oh yeah, it's says for me to call you if I am spiritually sick. It doesn't say for you to assume that I am spiritually sick and come over."
Always throw it back on them. Make them say that you are spiritually sick. Then tell them that they are operating from a false premise, and that you will call them when you need them. After all, that is what the bible says. Better yet, tell them you have doubts about all the nu-light. Ask them if it's true that ONLY the FDS can interpret the bible, then, how did you know all the nu-light from your own personal study?!?
The confused and depressed sheeple is a good tactic to use. Saying you started taking some new anti-depressants is also good. Whatever confuses them is best. If you don't want to be DF'd just yet, then don't come off as a rabid opposer.
Unless your friend is willing to play the " How did I know what the Slave knew" role, there isn't much they can do. The Eldumbs won't take him seriously if he raises a valid point. If the Eldubs are not sure how to handle you, then you can get away with saying, " My house is not on fire, nor could it ever burn down. It's built with fire resistant materials and the foundation is The Christ, Jesus."
It's all about what they believe and how they perceive you. OR...just nod and head bob. Then continue with your life. They will tire of trying to encourage your spiritually weak ass.