What Causes Metallic Taste In The Mouth?

Hi my husband is 40 and has a metalic taste in his mouth, he is having a hard time focousing with his eyes, he is weak and seems to be short of breathe, he has been like this for about 3 hours. He has had to lie down. should i be conserned. we have been together 16 years and i haven't seen him like this.