In your case also if they don't want to miss the tour, the person who should be with the elder can stay back and others can proceed. If no elder person to accompany the children he has to request somebody to go with them and take care of them. Otherwise only way left is to postpone the journey for some days.
'Idhuvum Kadandhu Pogum "
Even this challenging situation would ease
Elderly members, especially, must be cared for. Your friend cannot just leave the person in that state. Instead, your friend can explain to the children about the seriousness of the situation, namely the bad health of the elderly member, and say that the trip may be possibly arranged for in the next vacation.
When people come at you with their worst, you should come at them with your best (advice given to Selena Gomez by her mother, quoted in Time magazine.)
And I remember one situation about my relatives, they have a small kid around 5 year of age. He got fever once, at the same time they have their close relative marriage. There are no other people to take care of the kid. So they decided to take a kid with them to marriage thinking that it was a normal fever. Next day after the marriage, they took kid to the docters and docters said that it was not a normal fever it is a dengue fever. They have given the treatment, but the kid was dead. It was so sad situation, all other relatives have blamed the kid parents for not taking care of the kid.
No one can tell what will happen next. If some thing bas happens, we can't go back and correct our mistakes. So we have to take of the unhealthy persons. Even if some other persons were there to take care, the unhealthy person will feel better with his/ her beloved one presence.
Never neglect the unhealthy people, take care of them. Ones life is more important than trips.
Can't understand one point - when the whole family wants to go on tour, there is no point in the else going for the tour when one can't join it. Better to cancel and re-schedule it based on seasons.
Thanks & Regards
Children will definitely understand the situation better than even adults. Alternatively, depending on the situation ( that is there is nothing to worry about the ill health and sick person) and if the sick can be taken care of by the persons who stay back, then others can proceed on the tour and holiday trip with making necessary changes if needed. However it is not sure whether they will enjoy the trip as one of the family member is sick.
We had occasions like that when we postponed or even cancelled the planned event, whether it is a tour rip or any other event. My own marriage was postponed when one of my close relative fell seriously ill.