His family said he was 6’3’'. Do you only believe them when it suits you?
This should be a good object lesson for you. Let’s work through it. What’s more likely to be true, the coroner’s report, or his parents memories? I’d say the physical evidence, that is, the report. So, his parents must be lying. It’s impossible that they could be mistaken, they have perfect recall, just as you imagine Zimmerman should have.
Or, we could assume it’s a mistake. Not that many people would know exactly how tall someone else is, even someone close to them, unless they’ve had reason to measure them. I’d guess all they were really sure of is that Martin was tall, and I’d also guess that, as he was skinny, he looked taller than he was.
So, who was the “bigger man” as described? Well, Martin is at least four inches taller, which is hard to miss even when they’re on the ground, and he was wearing baggy clothes, which might have disguised his skinniness. Zimmerman’s weight was described by the police as 200lb in February last year, and 185lb in April, when he was arrested. Without knowing for sure, I’d take the latter to be more accurate as they would pay more attention at the point of arrest. Certainly, he didn’t lose 15lb in two months. Zimmerman was certainly heavier, but not massively so, certainly nowhere near the size he is now. 30-40lbs heavier than Martin seems reasonable.
So, who’s the bigger man? Is it Zimmerman, beyond reasonable doubt? Would any reasonable person, seeing the two of them, say Zimmerman? No. We can’t conclude from someone saying the bigger man was on top that it was definitely Zimmerman.
That is how to analyse evidence, compare witness statements with physical fact, and see what conclusions can be drawn from it. We learn two things. Firstly, memory is extremely fallible, even in circumstances where we might expect it not to be. Secondly, there is no clear-cut answer to the question “who was bigger”.