Upvote:3
It is certainly possible to reapply, but with or without a sponsor, they will want to see the applicant's finances and will be on the lookout for "funds parking." Even with a sponsor, they will look at the applicant's bank statements and refuse applications writing "I need to assess your own personal and economic circumstances" if there are discrepancies. Large unexplained deposits are suspicious and need to be documented and explained. In short, they are worried that she may have simply borrowed funds for the purpose of a visa application.
Please see our answer at Should I submit bank statements when applying for a UK Visa? What do they say about me?. A future application will need to clearly show her husband's income. If you see the supporting documents guide, you'll see that a letter from his employer stating his salary, paystubs, etc... is helpful. As he is self-employed, this is more difficult. She will need to attach evidence that shows the source of these funds: invoices, receipts, tax paperwork, accounting statements for the business, etc... Everything should match up and show a coherent picture as to where the money is coming from and that it legitimately represents their income.