Why have they contacted you? Are you a child care provider? If so, I imagine guidance will be given soon.
As others say, this is all new territory, so everyone is feeling their way. If a non-key-worker job can be done from home then I would ask the employer to do a risk assessment before returning to work. One person could return to work, or maybe each could go work on alternative days/weeks.
Schools are being given advice as to how to manage the environment to make it safe for everyone. It could include only half the children going in, for half the time, meaning more space can be given to them. I’m not sure teachers would be any more or less likely to need to self-isolate than any other section of working age society.