My Husband Is Training A Man Who Has Borderline Personality,

My husband is training a man who has borderline personality, my husband works in a high risk job working with machinery, so the problem is, the man with this BPD is not competent in doing the job and went to the bosses regarding the situation, my husband says he stares and daydreams and asks random weird questions about nothing, the bosses have really dismissed the situation and that he has a mental health problem and wont include my husband into telling him the full story about this man with BPD this man is a high risk and now my husband has to train him again, My husband is worried and concerned about this man and is a risk to everyone regarding safety. Is it in the best interest of the company to let this man go or the duty of care of bosses to let my husband know more of the mans mental health . Can you please help me regarding this situation. Dee