Solicitors duty as co-executor when there is hostility or conflict of interest

[charlie.b]

Should a solicitor that created the will and is a profit sharing co-executor allow the other executor to apply for grant of probate as sole executor if they are aware that:
1. The executor is hostile to one or more beneficiaries
2. The executor has issues with their finances that may influence them to executor the will unfairly or not as the testator intended

How would you challenge said solicitor in such a situation to act?