The net worth of FnF is not important for a release. What is important is that CET1 meets the required minimum. This minimum (FnF combined) is currently about $195 billion (= 2.5% HERA minimum of total assets).
To implement the capital raise, it would be sufficient for CET1 to increase to $55 billion: According to the 4th Letter Agreement, a maximum of 2 x $70 billion is allowed for the capital raise. This adds up to the required $195 billion.
CET1 is currently about -$138 billion. If the SPS were to "disappear" (whether by cancellation or conversion), CET1 would increase by $191 billion. We would then already be at $53 billion.
This means that the capital increase could be done right now, no matter what FnFs' net worth is.