I am in the waiting period (iddah) after a death, so is it permissible for me to see my husband's brothers?

The husband's brothers, if they are not mahrams to the wife, are like strangers. It is permissible to see them without lust, but it is forbidden for them to see her except with a full hijab. Seclusion with them is also forbidden. However, if they are mahrams, it is permissible for her to speak with them and shake hands with them, provided there is no fear of temptation, and for them to see what mahrams usually see, such as the head, neck, hands, and feet.