I looked around the hospital, feeling fulfilled.
fulfilled is an interesting word. but I'm not sure it fits right here. was the hospital feeling fulfilled?
I had also established
The "Save Our Environment" organization which aimed at providing a cleaner and healthier environment helped me to reduce malaria to the minimum. I had also spent many years providing free education and public health for the people of Nigeria. With the help of the Nigerian government, I was able to improve the medical system in Nigeria.
This appears suddenly, as another organization that you make by this time in your life. The last sentence reverts back to the hospital theme. im not sure these two connect.
Interesting second paragraph. Maybe work on the transition into you reminiscing. Also, make sure you keep tense consistent. You combine a general looking back. a drifting backwards...with the patient event. you talk about a lot, maybe focus more on one aspect. the hospital, the change, the influence, the needs, something that an autobiography would and could more likely talk about in depth.
great approach to the prompt. somewhat full of too much information. the overall idea is clear, but maybe elaborate on one part and not so much on separate events/changes in Nigeria