Ok - well you should NOT offer to pay this.
If he is in prison and Court papers come through then you should reply to the Court giving his prison address
You are not liable for the debt and you should not offer or pay this.
Then if proceedings were issued he would be able to admit the debt and offer £1 a month as he is in prison
But you should not in any way offer to pay it
In any event when he is released if he does not have any income he should only offer a minimal amount/
He should NOT borrow from his credit card
Can I clarify anything for you about this today please?