visit visa - student dependent's parent

[Shreakh]

hi, I'm an international student studying a MSc program in the UK and my wife and the child (3 years old) are also living with me in here as my dependents (student dependent visa). Can I bring my wife's mother as a visitor to the UK? I have a genuine requirement as well for this but I don't know if I can be a sponsor for her as she is not my mother but my wife's. Appreciate your guidance. Thanks.

[manci]

You can sponsor anyone you like but your mother-in-law's application will be decided primarily on her circumstances in her home country and on what she says about the purpose of her intended visit.

[secret.simon]

I have a genuine requirement as well

What is the "genuine requirement"? If it is to care for your child/her grandchild, keep in mind that that may be construed as working while in the UK on a visit visa, which is forbidden and which can lead to a refusal.
Better to state something on the lines of her wanting to spend more time with her grandchild.
Also, the crucial question is, given the situation in Sri Lanka, how would you and she convince the Entry Clearance Officer that she will return to Sri Lanka before the end of her visit visa? What are the ties to Sri Lanka that would outweigh her links to the UK (her daughter and grandchild)?

[vinny]

See also Inviting visitors to the UK
Inviting your family and friends to visit