If you plan to do some extraordinary thing according to your parents' eyes, try to prepare them to changes. Of course if you made a decision and took responsibility for unknown result. Personally, i believe in this inner voice and calling:)

It depends on the circumstances in which he/she lives but they should try to convince to the family by its logical points with its own capacity or skills as compare to others. If he/she can take responsibility for whatever the outcome so it should go for it but stills having wisdom instead of emotions. I having the same experience ..................................................

Not sure what you are asking for.