The father of the 11-year-old revealed his son was "very shook up".
He added: "These guys had guns, they put a gun to his head and they put a knife to my mum's throat, which is his grandmother, then they put a gun to my dad's head."
The young boy was crying and screaming but the gang "weren't bothered" as they "grabbed" him and "threatened to tie him up and strangle him".
The men fled the scene and hopped into a Range Rover, before running on foot "when the immobiliser kicked in".
A screengrab from the front door of the property
Before rummaging through the mother's handbag, the thieves asked the family to "arrange" for cash to be handed over.
The mob, who were equipped with cable ties, fled the scene after the man's brother arrived.
Around 20 neighbours later turned up after being alerted to the incident on the estate's WhatsApp group.
A spokesman for West Midlands Police said: "We are aware of CCTV footage circulating on social media showing a number of men trying to steal a Range Rover from the drive before running off.
"We are in the early stages of our enquiry and would urge people who may have information to please contact us via Live Chat on our website or by calling 101 quoting crime investigation number 20/822417/23."