help on refusal on visitor visa 2 the UK

I need some help with visitor visa.

My uncle has been refusal visitor visa for the UK as he is also young (24 years old).

They refusal it on the following,

As evidence of your circumstances and income

Tax returns- I note that these are readily available for self completion and are in effect a self declaration of circumstances. I note that these appear both newly issued and completed in the similar handwriting. Documents of this kind are readily available for nominal fee in the Pakistan and as such are little evidential value.

Receipts- these do not by themselves, without supporting accounts, provide evidence of an established business that generates a regular income.

Affidavits – these are produced and attested by official without the need to produce any substantiating documentation. They are, in effect, a self declaration, base solely on the word of the declaring party.

I am not satisfied for the reason given above that the document provided give satisfactory evidence of your employment and income.

He owns his own shop in Pakistan, as you are award that in Pakistan small business do not pay tax, the reason he made the TAX paper was that someone told me that they want to see TAX paper.

Also when he gets goods for the shop the receipts he gets on handwriting also he has not been keeping them.

So I need help what shall I do now.

How can he proof he has a business

Thanks
Yasmin