Any source to this news or it is just another HOAX  

Facebook won't put their hand in something that they never have experience with. May be Elon Musk will buy coinbase but surely not Zuckerburg because MUSK have some experience with finance related startup but zucker is more into media market. He even can't make proper decision and quickly announced the complete ban of cryptocurrency related ad which he recently modified. Every government is having close eye on this young self made billionaire ..