HR furlough resignation advice

Dear HR,

We need advice please.

A member of our team joined in September 2019. With a 3 months probationary period. His manager has found him to be ineffective and misleading when carrying out his responsibilities. She had a discussion with him regards some of if his performance earlier in the day. Later in the day she followed up with an email pertaining to their discussion two days prior in that we would need to furlough them. However, she updated him that the business would be unable to top up the individuals salary Over what the government was offering. This took place last Thursday.

This morning, the employee handed in their resignation via email.
We need some advice around this please.

Thanks
Nicky