Elon is selling his Bitcoins ...
I am disagree with you. Elons Bitcoins could not be sold so quickly. It is not so easy to sold right now. Companies around all world want to buy bitcoin right now, we should to see a big run = to the moon.
It's possible he could've but it wouldn't have had much significant impact on price, when bitcoin's 24 hour volume is around $40-70 BILLION where Elon only had 1.5$ Billion.