Is this sex discrimination?

[Dgall]

I'm due to end maternity leave shortly, and DH has requested to drop to 3 days a week when I go back to work to look after our DD as I earn significantly more than him.

Today he had a meeting to discuss this, and it was refused. That was always a possibility, so initially wasn't a huge issue (although obv preferable for us not to have to put her in childcare full time if we don't need to)
However, DH asked why there were women that were able to drop days/job share if 'job sharing doesn't work in this department' and was told that it was different because they recently returned from maternity leave so a bit of flexibility was needed for their childcare requirements.

Is this sex discrimination? His request for part time hours so that he could look after our baby was refused but a woman who requests it to look after her child after maternity leave is agreed because flexibility is needed?

If it is, is there anything we can do? He has been told he has 5 days to appeal in writing.

workingfamilies.org.uk/articles/flexible-working-and-the-law-a-guide-for-employees/

Direct Sex Discrimination
Men cannot claim indirect sex discrimination for childcare reasons. However, a married man or a man in a civil partnership might be able to claim indirect marital discrimination, if without justification, he was not permitted to work flexibly, and suffered harm as a result. Also, if a man is refused flexible working in a situation where women doing similar jobs are allowed to work flexibly, this could be direct sex discrimination.

Direct sex discrimination is where an employer either treats men less well than women, or women less well than men. Where an employer treats someone less well, for instance by changing that person’s work pattern, for a reason connected to pregnancy, childbirth, maternity leave or breastfeeding, this is also direct sex discrimination.

They should be making flexible working decisions based purely on the role. The reasons the person is asking should be entirely irrelevant. So yes, if they would have said yes had he been a woman, that is sex discrimination.