My friend graduated college and received his diploma but he couldn't believe that he did it.
Really? Why couldn't he believe that he graduated from college?
Because he never applied himself or studied very hard.
It's great that your friend graduated from college. You shouldn't be envious of him because it was easy for him to graduate. You should be happy for your friend's success.
I am happy for him but I had to work very hard to get through college and I wish things were as easy for me.
We all have different things that come easier to us than others, with some people it can be more apparent but its best to just be happy for your friend and work on what you can do to be better yourself. There isn't any reason to waste time being jealous of other's work.