When a claimant is paid PIP backpay they can have over £6k in savings for a year without it affecting benefits. If someone were to use this money to repay a loan (say for example a family member had been supporting them on a monthly basis on the understanding that the support money was a loan and the claimant would, one day, repay it) would that be an ok use of the money?
Your question is outside the remit of the forum, but as far as I'm aware a claimant can use that money for whatever they want. No one will be asking them.
BIS
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