family visit to UK

[shak80]

Hi
My mum is living in Pakistan with her older son in Pakistan. And older does not pay any tax but he is doing business. I applied for my mum visa in 2009 they granted her visa and she returned back on time.
She again applied for family visit visa. They refused because her son does pay the tax. I applied for appeal they refused because ukba want to his tax documents/business bank statement/profit and loss account etc.(he don’t have any documents)
Ukba is saying we are satisfied with sponsor(me) documents but not satisfied with brother tax and every time ukba bring my older brother bcoz she is living with them,(I don’t have any his tax documents)
I again want to sponsor my mum to visit me.
How I can remove my brother business from mother application?
Thanks
Regards / Shak