Entitlements of the employee upon termination for redundancy

My brother was terminated yesterday and the reason is to reduce employees upon instructions from our UK office.

He’s with the company for 3.9 years under unlimited contract and given the 30 days notice on 30.05.2019.

Is he entitled for 3 months salary compensation as per arbitrary dismissal/termination not related to performance?

He was advised verbally about this instruction and he was chosen. We would like to know his full benefits and rights, please.

Thank you in advance.