Just to clarify, he's jumping a BASE rig with a wingsuit - albeit technically a skydive (jumping from a helicopter).
It's a BASE rig since it only has one parachute, and the sole canopy is designed to deploy quickly and consistently.
Another clarification - BASE rigs with wingsuits are not inherently dangerous. In fact, BASE/wingsuit gear failure as a cause of death is extremely low. It's correlation vs causation - BASE rigs are used almost always (except for certain stunts like this) used in a BASE environment flying close to land, where the margin of error (time to impact) is extremely low compared to a skydiving environment.
In a skydiving environment, you can do everything wrong, even do nothing and likely live (automatic activation device triggered deployment of your reserve canopy). But with BASE, oftentimes you are flying so close to terrain that you cannot deploy your canopy and live, and your only option is to continue flying your wingsuit to a safe place to deploy - which is a problem if you stall, take a slightly wrong line down the mountain, etc.
Source: I'm a parachute rigger and I wingsuit (in a skydiving environment).