A TRACON Controller reported that a helicopter did not fly the Obstacle Departure Procedure and flew below the Minimum Vectoring Altitude.

Narrative

Aircraft X checked in as an IFR departure from ZZZ to ZZZ1. The D-side then advised me that they had released Aircraft X from ZZZ; I assumed that Aircraft X was on the ODP (Obstacle Departure Procedure) but did not immediately have time to look at their flight plan as I was busy with other tasks. I radar-identified Aircraft X and observed them level at 080 about 3 miles NW of ZZZ. Later during my scan I noticed that Aircraft X did not appear to be flying the ODP and questioned the D-side about the flight plan; I looked at the flight plan and the routing was not consistent with the ODP nor was it consistent with the route that the pilot was flying. I questioned the D-side what they had issued to the ZZZ tower controller but did not get an answer. I waited until Aircraft X transitioned into a lower MVA where I could vector them and put them on a heading; but for most of the time prior they were in a 160 MVA at 080.The D-side should not have released the departure if they didn't know what the route should have been. I should have issued a low altitude alert as well as re-cleared them to ZZZ1 once they were in an area where I could issue vectors.