Applying for a fee waiver

Basically I have a wife whom is of Indian nationality whom gave birth to my son in the UK during being present on a tourist visa.

We are now currently in India as she has left due to her visa being about to expire.

Simply cannot afford to pay the visa fee amount for a spouse visa or satisfy the requirements but do believe qualify for fee waiver under the exceptional circumstances rules.

I'm disabled myself and my young son whom is a UK passport however cannot return to the UK without his mother obviously as she is an Indian citizen.

We are currently paying a fixed amount each month to the NHS to cover her maternity bills and have reciepts.

Is there any official way of applying for the fee waiver and what is the form used for applying for indefinate leavet to remain given the routes available?

Any advice would be gratefully recieved.

She doesn't qualify for indefinite leave to remain. She needs 5 years residence before she can apply for ILR.

She needs a spouse visa to return to the UK.