I keep visiting Dubai
Not sure what kind of work it is, assuming it regular job.
For the period mentioned above I was out of India for more than 182 days,
If you were out of India for more than 182 days in a given financial year then you would NRI for tax purposes.
till date I have not transferred any money from Dubai to my India account.
Whether you have transferred the money or not is not relevant for tax purposes. Your status [NRI / Resident] is relevant.
Do I need to declare the income I have earned in Dubai?
No you are not required to as your status is NRI. You are required to file a return on the income [Salary/Interest/gains/etc] accruing in India.
Do I need to change my residential status ?
Not sure where you are wanting to change this.
Will the income I have earned in Dubai is taxable ?
As you are NRI, the income earned outside of India is not taxable in India. From a tax point of view, it does not matter whether you keep the funds in Dubai or transfer it back to India.
The Income Tax rules are not very clear if your wife can claim for her father-in-law. Best consult a CA. For quite a few regulations, Wife's father-in-law are treated at par with father.