Equality and Human Rights Commission

The duty to make reasonable adjustments to remove barriers for disabled people does not apply to non-disabled workers who require adjustments to take care of a disabled person with whom they are associated. People in this position, and those assisting children and older relatives (whether or not disabled) with their day-to-day care needs, are often referred to as carers.

Most carers will qualify for the right to request flexible working once they have worked for their employer for at least 26 weeks.

An employer also needs to think about whether refusing a request for flexible working may be direct or indirect sex discrimination, as explained here

The protected characteristic of the person with whom a worker is associated may be relevant if an employer makes a decision based on that protected characteristic.

For example:

An employer offers flexible working to all staff. Requests are supposed to be considered on the basis of the business needs of the organisation, but a manager decides that a man’s request to work flexibly to care for his 90-year-old father is more important than another man’s to care for his 50-year-old wife. If the manager’s decision is based on the age of the person being cared for, this is almost certainly discrimination because of age by association. (It would not be unlawful if the decision was objectively justified, since direct discrimination because of age, unlike because of other protected characteristics, is allowed if justified.)

If the manager made their decision based on the fact the person with whom the worker was associated was a disabled person rather than an older person, that too might be direct discrimination by association because of whichever protected characteristic lost out. The manager should base any decision on the business needs of the organisation, not on the protected characteristics of the people making the requests.