Yes, Families' Days are currently suspended.
COVID-19 circumstances will inevitably impact predicted leave dates. Put bluntly it's difficult to predict.
CTCRM is a training establishment with perhaps 700 plus personnel on site at any one time. In many ways it is comparable to a university campus, except nobody yet appears to be weeping out of a window for the benefit of TV media.
Your chap will undoubtedly keep you updated when he knows what the plan is. Prior to COVID-19 long weekend leaves were more predictable.