I824 process and need a travel advise

[haisylu]

My wife and I have GC but our Son's i485 has been denied. He is 17 and turning 18 next March. Now we are going to apply i824. Few questions:

1. What is the road map for i824 and the processing time?
2. Also, is it ok to travel thru Europe to India since his current VISA is expired?
3. Also does he needs to leave US before he turns 18 or any time before he hits that 180 days after turning 18?

Thanks for your time.

[kmrj50]

I also need to file for I824. Curious to know how long did the I824 process take.