Gandee, 21, was found dead, along with his uncle and another man, in a truck in West Virginia Monday morning.
The cause of their deaths had not been officially determined, but the entertainment news website TMZ cited law-enforcement sources as saying they likely died of carbon-monoxide poisoning after the tail pipe of the truck was submerged in mud while they were inside.
The circumstances of the trio's deaths also were under investigation, but the men reportedly were off-roading after a late night out at a bar.
Gandee's cousin, Ashley, told TMZ she is setting up a memorial off-road trucking event in Proctorville, Ohio, to help pay for her relatives' funerals.
"I know the strain they are going through," Ashley said. "It's hard to provide a proper burial. It's already tough with the loss of family members ... expenses are tough as well."
The event, which costs $10 to enter, is to take place about 50 miles from Charleston, W.Va., where the MTV reality show "Buckwild" is filmed.