So saddened to hear this. I'll be praying for his family. I will miss Brent's amazing photos here on UHH.
Based on my experience, I would discourage you from taking a large prime lens on a safari. The distance needed will vary greatly, so a zoom is much preferable. If you are able to take two lenses, my first recommendation would be something like a 24-120. Then a longer zoom, something like your 150-600mm would also be nice to have along.
I agree with Bill's response as well. If it says sold and shipped by Amazon, you are protected.