Visa for a South African

[Lenka]

My husband is a S African who lives & works in the UK on a Spousal visa. The company that he works for agreed to apply for a working visa for one of his S African colleagues, who also worked at the same company previously but then had to return to SA when his visa ran out.
The company are now saying that my husband has to pay a fee for this visa & that he is the sponsor. I am sure this is not correct or legal since I think you need to be a British National to sponsor someone & also surely the company who are applying for the visa should pay.
Can someone please advise?