It depends very much on whether the court views the loss of job as a deliberate tactic to reduce the Ancillary Relief award.
They will look at how he lost job (did he just quit, was he made redundant?).
And also at what efforts he is making to get a new job.
But short answer to your Q is ...yes...it is not the best time to divorce him.
You do stand to get a better Ancillary Relief outcome if he has a good job at the time of the hearing. But remember AR takes a while to go through the courts and so the FDR/Final hearings could be in 6 months time.
Can he afford to stay out of a job for that long?
The court can apply the concept of 'earning capacity' to a case where one party appears to be deliberately under earning. Then they make the award based on his/her 'earning capacity' rather than actual current earnings.