A TRACON Controller reported a Cessna departing in marginal weather reported their Attitude Indicator failed and they needed to return to their departure airport. The Controller vectored the aircraft below the Minimum Vectoring Altitude to assist its return for an approach.

Narrative

Aircraft X was released off of ZZZ with a heading on 230 and an initial altitude of 4;000 feet was assigned for IFR flight from ZZZ to ZZZ1. The heading was assigned due to an approach at ZZZ2. on departure the aircraft came up squawking the wrong code was instructed to squawk XXXX and subsequently radar identified. Shortly after the aircraft declared that his Attitude indicator had failed and the weather was MVFR. The aircraft at this time requested to return to ZZZ on an RNAV approach. Again shortly after this interaction the Pilot stated they needed lower and to immediately return to ZZZ. I at this time game the Pilot a left turn to get them over ZZZ3 and [gave priority handling] for the aircraft as well as advised them of the MVA for that area. At some point thereafter the pilot declared that they were in contact with the Ground. I asked how many were on board the aircraft and if the could see the road as well as the status of visibility and engine function. the aircraft was able to stay over ZZZ2 avoiding power lines to return to ZZZ and a landing was completed. The aircraft was vectored below the MVA.