Support immigration letter

I need to write a letter to send along with a parson to immigration. My family came from Venezuela about 20 years ago and we live in Virginia.  My sister is trying to get my dad to become a permanent resident and it was denied. We are forming an appeal with a lawyer and wants letter from family members and friends.. In the letter, needs to talk about him and how good of a person he is  and explain how our family would suffer extreme hardship if his residence is denied and he would have to leave the country. He helps us financially and takes my mother to doctors visits because she is unable to work at this time. She depends on him and this letter needs to be extremely dramatic. Also the letter needs to talk about Venezuela’s crisis and explain how no one can really live there right now. No medicine, no food, high crimes.