My son died in afganastan and his mother who I have been divorced from for years hid my exsistence?

i was not notified by the military correctly and was left out of the obituary as well as my children were. My children did not recieve acknowledgement for being his siblings or anything. My ex wife has taken all of his personal possessions as well as all of the life insurance money etc.. leaving all of his siblings with nothing. Can I sue her for a part of the life insurance for his siblings?