1. Essentially, you simply write back to the landlord and inform him that you were in no sense the guarantor of your brother's tenancy and you did not sign any guarantee. Make clear to him that you are not liable for any monies owing by your brother as you never signed any guarantee nor did you agree to act as guarantor. Otherwise, you face the choice of being liable for any money your brother might owe this ex-landlord. Be aware that in law, guarantee is a unilateral undertaking to be liable for someone else's debts. However, in order that a guarantee be binding it must be freely assented to by the person becoming guarantor. As you did not agree here, you are not bound by any guarantee.
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