When I worked for GSK in HR they reckoned that a mid-level person would need 6-9 months to find a new job after being laid off. More senior people, a full year. This did not take into account the present, extraordinary circumstances.
I agree with this.
I am sure your dh is already doing this but go for maternity cover or contract/consultant roles (especially project-related where they only need help for a temporary time) which are more likely to be at his senior level.
At the risk of stating the obvious, I hope he has set up job alerts on Linkedin and Indeed. Some of these roles are advertised directly on the company websites rather than through agents. These alerts sign post who is looking and in what area in real time. If a role comes up, he can then leverage any industry contacts to try to get an inroad. It is much easier to go in more strongly once a role comes up than to 'cold-call'. If he can find a good recruitment agent (lots of sharks out there, unfortunately, who exploit candidates), they are prepared to sound out potential employers they have a good relationship with, especially if they think your dh is experienced with a good CV.
It may take a year or more for a job hunter to find a senior level job
but the same can equally be true for the employer. Therefore, a good matchmaker is prepared to put your dh out there, even if it is speculative, because it is finding the right fit for senior roles.
Good luck there. Something will come up.