Irritable, Mood swings, Acceptance issue

Hi - The problem I am writing to you is for my mother. She is 57 years of age. From last many months, we have observed her getting very intolerant, impatient and always complaining. She gets very irritated over small things and snaps off very often if things aren't in her way. She has also developed a practice of exaggerating her issues with people and situations. If we try to convince her to see a doctor for her situation or try to check what is bothering her, she is unwilling to accept that she has a behavioural issue but feels everyone around her has a problem. She interprets it as we are trying to tell her she has gone mad and needs to see a "mental doctor". All of us at home are very concerned for her well-being and not sure what we can do to help her