Just to add on what has been suggested above , I would suggest that you get in touch with a local brain injury rehab unit and request to speak to occupational therapist or nurses to advise you on the basic skills when relating with your son.
This would help you deal wwith the immediate which is you. With these skills you become aware of your feelings and therefore your behaviours towards him when he seems to become unreasonable, ..."He has changed some of his ways"..but you are still relating to him as the son before the accident. What has changed is the organic configuration of his brain and therefore functioning..You therefore need to learn to relate to him and he would then reciprocate to your new ways. Rehabilitation is about re-learning not only for the "service user" but to those in his/her social environment.
Look out for a local carers group as they do have invalauble experiences.
