UK General Visitor Visa Parents

[nanipals]

Hi All,
I need an urgent help from one of you.
My Parents applied for a general visitor visa and got refused. The reasons are:

My Father's Application refused with the following reasons:
1. No evidence of employment and income from employment : He submitted employment letter but it was lost some how.
2. Evidence of a lump sum deposited into the bank account in March of this month

My Mother's Application refused with the following reasons:
1. No evidence of income from her self-employment.
2. No evidence of lump some in the bank (around 400k)

Here, the issue is :
My father can apply for visa again with proper documents. He received some amount from his provident fund(from previous company) in the month of march. then he has some balance in his account from previous year. this can prove evidence for source of funds. He is employed with a company which pay salaries by cash.. I dont know how to show this.Could any one please help me by suggesting me how he can prove it.
He applied for tax returns and it proves his employment.
\BUT Big problem is with my mother's application:
My mother is self employed. She is doing some catering business. But she does not have any company on her name. She regularly submit tax returns . this year, she earned around 630k per year but expenses are near to 530k. She gets all the money in cash. For marriages and few functions, she makes special dishes and supplies. She also has few tailors, who design bridal dresses and supllies. the problem is : how she can prove this as all transactions are in cash.
Please help me , it is very very urgent. My wife is pregnant and want my parents with her for next one or two months until her parents come to UK for delivery. Please help me by suggesting something.. Please guys..

[studio123]

whats ur immigration status ? can you show ur saving for your mum ?

[nanipals]

whats ur immigration status ? can you show ur saving for your mum ?

I forgot to mention: I am from India. My parents applied visa in India.
Their bank balances are:
around 450k Indian rupees( for my dad) + 450k Indian Rupees(For my mum).
Thank you for the reply. I am on Tier-1 Visa. We gave(along with my spouse) a sponsorship lettter. We sent all our bank statements, pay slips, p60, title deed of the house. We have around £8000 in bank accounts that my parents supported in support of their application.
These £8000 (together with my spouse) is staying in the bank account for the last 5 months..