Hello and welcome to Healthcare Magic. Thanks for your query.
If his symptoms, like irritability, anger outbursts, negative thinking, etc. are of a recent origin and different from his usual self, then it is likely that they could very well be symptoms of an underlying mood disorder
On the other hand, if these problems are rather a part of his 'usual nature', then it is likely to be unhealthy personality traits.
Whatever be the cause, if it is causing significant problems in your family, then it would be worthwhile to consult a psychiatrist
for a detailed evaluation and further treatment. Depending on the probable cause, treatment can be in the form of medication or psychological therapies. Counselling
sessions focussing on anger management
techniques can be of great help.
Wish you all the best.
Dr. Jonas Sundarakumar