Hi there,
sorry for the late reply of this. [i wrote the original post]
oF course, I actually fileld out all the paperwork myself.
The bottom line is this --> they don't know you and don't know your case, therefore, you need to prove to them EVERYTHING including, that you are you (a copy of a legal document that proves that you are you), proof that the person you claim to be your father is your father (a legal, translated doc by an official translator like a birh certificate, and officilal doctor's documentation that explains his illness, translated to english.
also, remember that these are immigration officers and NOT doctors, so I also sent copies of explanations of the illness my dad has from a reputable site online webMD that explained his illness in detal.

I followed the instructions for the application to the T (meaning I read it over and over again) and made sure my packet was organized, like a story, so the immigration officers had an easy time understanding it.

here are the isntructions to the application. READ THEM SLOWLY. you'd be applying for #3 advanced parole http://www.uscis.gov/sites/default/f...i-131instr.pdf

-I first proved that I was who I said I was
- I then proved that my father was my fatehr with a copy of the spanish birth certificate and a translation attached to it from a reputable translating company
- I then proved his illness - provided copies of doctor's paperwork explaining his diagnosis. I included the spanish copies and the english translations
- I then proved that the illness was serious by providing an explanationo of the illness dfrom a reputable site (webmd).
- I then explained the reason why I needed to travel to see him (to help locate good medical care for him)
- note that the instructions say sending copies is ok. I NEVER SENT ANY originals in case they got lost.

my application was approved the first time around ==> it took about two months for it to go through.

let me know if you have any other questions

oh and ps. I worked for 1 year with an immigration attorney so that's how I learned to be methodical in submitting applications