If they are receiving a redundancy lump sum now that is greater than statutory redundancy, they may be given the option to waive their entitlement to a tax-free lump sum at retirement, in return for having more of their redundancy lump sum paid tax-free now. Or they can choose to pay normal tax on the redundancy lump sum now and there will be no effect on their retirement lump sum at 65.
If they are being offered this choice they should be shown the facts and figures relating to either choice. I would suggest that they should take professional tax advice in evaluating the two, before making the decision.