I would treat this as a club compliance issue now, not something to tidy up at the end of the season.
The club should know which current qualifications and safeguarding requirements apply to that coach’s role and whether they can continue in the role while renewal is outstanding.
Do not rely on “they did the course before”.
England Football first-aid qualifications have expiry periods, and safeguarding/affiliation requirements are also checked through club processes.
I would ask the club secretary or welfare officer to verify the coach’s current status in the relevant FA systems and, if necessary, speak to the County FA.
Then fix the system that allowed it to happen.
A central renewal list with reminders is much safer than expecting every volunteer to remember every expiry date themselves.
The key thing is not blaming the coach.
It is making sure the club does not knowingly operate outside the requirements that apply to its teams.