My brother has recently broken up with his disgusting, overweight, insane girlfriend

They've been together for 5 years and bought a house together about 2.5 years ago

The mug that he is put in about 75% of the money in including deposit/mortgage repayments/bills

Now since he whatsapped her on the way to work telling her it's over (I imagine with a little chuckling monkey emoji); she wants 50% of the house...does he have a leg to stand on?