How does he eat that amount of liver everyday without getting an overdose in certain vitamins and minerals, namely vitamin A?

Why do you assume he isn't overdosing on those vitamins and minerals?

Also, the fact he's on gear and also eating so much liver which is very high in iron, his heart and blood viscosity will be fucked.

An important point that Leo tries to mention a lot, is that looking good or strong, absolutely does not mean you have good health. I commend the guy on being in good shape and I'm sure his fitness routine is pretty impressive, but his actual health must be complete shit.

I doubt the guy gets any blood work done at all. He just seems convinced this "ancestral lifestyle" is ideal, and probably would ignore a doctor who told him the opposite. But as Derek pointed out, this isn't truly ancestral anyway, because he would be eating a lot more fruit, veg, nuts and seeds, etc, rather than eating so much meat.