Heilung came up with a clean bill of health, as far as I could find. No sign that they’re secret Nazis. You just have to worry when you discover a band you like that speaks to an imagined history loaded with nordic/germanic imagery.
On a related note: Heilung was basically a religious revival, when I went to their show. Just a crowd of metalheads with one hand raised in the air, swaying gently to the music, until the closing number when the gentlest mosh pit I’ve ever seen broke out.