Center Controller reported an aircraft that was in icing conditions and having to descend the aircraft below the MIA.

Narrative

Training on Sector X with severe icing and severe turbulence W of ZZZ1 airport. The flow of aircraft come from the W and the trainee was vectoring aircraft to the E where the icing was minimal. Aircraft X came to us at 130; which is too low to vector to the E; so we were vectoring Aircraft X around an area where we thought icing was minimal. We needed to vector Aircraft X because they were 3 or 4 in the sequence; so while not an ideal situation; it was needed. Aircraft X started reporting icing; so we started to vector the aircraft away from the known icing. It was at that point that Aircraft X reported severe icing and reported that they were unable to maintain altitude. Aircraft X also had a hard time accepting vectors from us; so it was at that point that I felt the situation dictated an emergency because the pilot was unable maintain altitude and a heading. We then descended the aircraft to as low as our MIA (Minimum IFR Altitude) allowed; but this was still not enough to get the aircraft out of the icing. While this was going on; another aircraft was on approach and that pilot was reporting when they broke out of the conditions. Aircraft X was on a 010 heading towards the airport and lower terrain when the pilot on approach to ZZZ1 reported breaking out at 110. Aircraft X was in a 120 MIA; so I told the pilot of Aircraft X that he'd break out at 110 and descended him to that altitude. I notified the pilot that while this was below my MIA; it was still a safe altitude because in mountainous terrain; 2;000 ft. below the MIA is safe. As soon as Aircraft X reported at 110; he said he was out of the icing and was regaining control of the aircraft. We need an emergency map to show high points in the terrain. We've been asking for this for years and management/NATCA keeps telling us its too much of a liability to show where the terrain actually is. This is my second emergency in two weeks and both times I absolutely needed an emergency map to show where the terrain actually is and where the high points are. We have the ability; but still no action from management or the union. Not having a terrain map is the liability and we will lose pilots if controllers can't see where the terrain is and try to keep aircraft in severe icing because they're too scared to make a tough decision. Also; when this situation happened; I was pulled aside immediately and scolded for descending an aircraft below the MIA to avoid a crash. At least they could let me decompress for a moment before I get berated for not doing the right thing. Even though multiple pilots said on frequency how well we handled the situation. I guess ZZZ Center would rather have pilots and family members crash; but follow the .65 to the absolute T; than use the rules we have during an emergency and have the pilot live to see another day.