I am disconnecting a bathroom exhaust fan that is vented to a roof vent in my attic. This caused condensation/moisture in my attic, which became apparent on these cold winter days. Some of the insulation is damp( I plan on replacing what is apparently damp). There are no signs of mold at this time. What do I need do so to don't have mold/rot problem in the future? Do I need to be concerned about the second floor ceiling drywall?
As Ed said in his comment, you need to reconnect your exhaust to the roof vent. Perhaps your question should've addressed that issue. It's not clear why you made that move.
I also agree that the insulation will probably dry out well with a little air movement. I'd place a fan blowing across the surface of the damp area, and be sure that you have good outflow. Apply a fan to a roof vent for a few days if necessary.
The drywall isn't an issue either, unless you have visible signs of water damage or mold. Even mold on the attic side wouldn't motivate me to tear it out.