It is possible to raise a mortgage where you are employed by your mother, father or other first degree relative within a family business. Typically expect to have to provide 3 months bank statements and 3 months payslips. Note this applies to applicants who are employed and have very little or no shareholding within the business.
For those who do have a shareholding at 25% LTV or more expect the average lender to treat you as self employed, and ask for up to the last 3 years SA302s / tax returns as evidence of income. I need to make it clear you do not necessarily need to trading for 3 years, one year’s figures will be enough assuming you started trading in 2014.