What happens if an essential working parent has their custody rights questioned because of their potential exposure to COVID-19?

Here are the guidelines from Department of Justice:

Prior agreements, whether it be a custody or access order or an agreement between the parents, for example in family mediation, must be respected as much as possible. However, in the current situation, everyone must apply common sense and respect the instructions issued by public health. Everyone must collaborate and comply with health regulations. Everyone has a role to play in reducing the risk of viruses spreading. This also applies to separated parents and families where a child may have to move from one family environment to another.

A lawyer from the firm Devichy was successful in a child custody proceeding involving a situation of essential workers potentially exposed to COVID-19.