I am Driving/dropping a patient from a skill nurse facility in a official handicap wheelchair van, could I leave the vehicle in the drop off area? while I help her check in... Or the van will be a trouble! maybe for 30-40 minutes.

Yes the parking terminal may be better. BUT considering your situation find an agent and ask them directly. They maybe able.to make certain arrangements to help you better. Never hurts to ask. Right

I would inform the airport of your needs they often make accomodations.

I don't think that is a good idea. There are parking levels across from each terminal that are free.