Of course Dr.Kennedy is right. Since my eldest son and I have the same problem with hearing voices, I thought I would mention it since your care provider can also have his auditory processing checked while treating for the stressful experiences your child is having. Both my son and I have an auditory recognition problem, which occurs mainly at certain tones. How it was explained to us was that because some of the auditory signals to the brain are not functioning correctly, our brains try to "make sense" of what the signal is. Our frame of mind shapes it from there, and typically it is interpretted as men speaking but we can't quite understand the words. There have been times it sounds like distant yells or someone crying out. A stressed imagination can certainly put a negative spin on it. However, we recognize for what it is, and adjust accordingly to the way our brains resourcefully try to compensate for our auditory problems by "filling in the blanks". It certainly may not relate to your son, but, while seeking psychological support for his stress, it may be worth checking.
You should seek mental health evaluation for your son right away. Even without the particular symtoms you describe, the traumatic family events themselves invite urgent evaluation.
accidentally posted the rest of my story under pediatrics community