I would never attempt it on any vehicle with actual ABS brakes.
We still use Kelsey Hayes Hydraulic Brake Controllers in the 1st generation Cummins world as they are still the best way to stop a trailer smoothly,reliably time after time. Our trucks have basic abs on the rear axle only so we tap into the front brakes.
Of all the 1st gen owners I know of on separate user forums no one has ever heard of a failure. These units fell out of favor though at pressure from OEM and insurance companies. In Australia they are banned.