Visit Visa Refused- HELP!

[mansoor123]

I submitted an application approx. 2 weeks ago on behalf of my uncle (resides in Pakistan) to visit the UK. It is urgent in nature as his brother is currently in hospital with covid complications. The HO have refused the application for a visit visa because they're not satisfied that he meets the requirements of paragraph(s) V4.2 of Appendix V because:

You are applying to visit the UK for 1 month in order to visit your brother and his family.
I recognise that family visits are important and I am aware of the circumstances surrounding
your visit. I must consider the information regarding your sponsor’s support of your visit
separately in my assessment of your application. To consider whether or not I am satisfied
that your intentions are as stated and that you meet the requirements of the Immigration Rules
I must assess your own personal and financial circumstances.
You have stated that you are self-employed as a land agent and that your total annual income
from this employment is PKR800000 (£3692).You have stated you have £12000 as savings.
I have noted all of the documents which you have submitted in support of your application
including the land documents, FBR document and bank statement in your name account
number ending 9982 covering the period 01/03/2020 to 03/03/2021. I note the total credits on
your bank statement account number ending 9982 is PKR8585000 (£39623) for the reporting
period. This amount credited 10 times your stated annual income. The remaining documents
do not demonstrate the origin of the funds held in your account. On the documents before me,
I am not satisfied that you have given an accurate reflection of your personal and financial
circumstances. This undermines the credibility of your application to the extent that I am not
satisfied that you are a genuine visitor who would leave the UK at the end of your proposed
visit.
I am therefore not satisfied that you are genuinely seeking entry as a visitor and that you intend
to leave the UK at the end of your visit. Your application is therefore refused under paragraph
V 4.2 (a) and (c).
Rate of exchange £1 = PKR 215.37

All of the funds are legitimate - he only has 1 bank account that he uses for both personal and business purposes. His tax return shows a low income against the total deposits made into his account - this is due to investor money and commissions earned. What kind of proof can we submit that would satisfy the HO of the origin of the funds? Any advice would be appreciated...