Sunday night he’d have been fine as he wasn’t expecting to hear from her. I’ll bet he didn’t sleep well on Monday night, he would have been fretting by then. But… not knowing the area and phone signal coverage, while being all too aware of the kerfuffle caused by calling out mountain rescue, at night, during lockdown, I can kind of see why he’d have left it until the following day. I am sure he regrets that now and always will
Of course, we don’t know when the alarm was officially raised (there is a discrepancy in reporting) but I’d imagine there was a flurry of calls and messages to Esthers parents / friends, and frantic attempts to track her phone before finally making the emergency call.