Did the org have any guidelines on shunning?
Yes, especially if there are minors involved.
If the son is d/a or d/f, are the parents supposed to disown him, chase him out of the house?
Not physically if they are minors since they could get in legal trouble for doing that. If they are not minors, many JW parents choose to kick them out of the house, but there's no written rule about it. However, if they live under their roof and are being supported by them, they should abide the rules of the home owner and the person who is providing and supporting the son/daughter. Emotionally, yes.
Also, some JW loving parents look the other way and still do the right thing and don't disown their children over some Jehovah nonsense.
For husband and wife, do they need to divorce or what?
Not necessarily, but if the d/f or d/a a person is the woman, she has to be "submissive" to her husband, and he has the opportunity to do and treat her any way he wants (or any way he can get away with legally). If the d/f or d/a person is the male, then the woman has to go through a whole load of nonsense to balance still being submissive to her husband and fulfilling the demands of the Jehovah nonsense.
I am very lucky. My parents still give me allowances when I go school. When I sick, my dad still bring me to the doctor.
You are not lucky. Your parents are legally bound to do so. That is their responsibility and duty to do. They have to do that if you are a minor under their guardianship. When you turn legally an adult, then you could say if you are in fact lucky. Also, taking care of you as a child should not be a matter of luck. All loving, responsible parents should be more than happy to support their children.
When I tell them that they are suppose to shun me, my dad told me he still need to fulfill his duty as parents.
See my comment above. I find it sad that he doesn't say that it's because he loves you and wants the best for you.