Nobody in the thread is concerned that the kids are going to Hell. This isn’t about sin.
It is about teaching kids about the reality of our obligations and duties. Mass was not made obligatory on Sundays and Holy Days because our bishops wanted to put a big flaming hoop between us and heaven. It was made a duty because they do not want us to lightly evade such an important means of obtaining grace for ourselves and for others.
This is something I remind my own children of when they don’t feel like going to church. In our family, we have a certain attitude towards duties and commitments. Our church commitments are as real as any others. Just as we are missed by other students if we don’t choose to attend school, we are missed if we choose not to attend and participate at Mass.
You make an important point: just as you should not force yourself to go to school or work when you are sick and should stay home or just as you might need to miss work because your freezer broke and all your food might be lost, there are legitimate reasons, too, for missing Mass on a day when it is normally obligatory. It is just a bad habit to let that bar get too low.
It may be that the OP cannot get her children to Mass without putting a severe strain on her relationship with the children’s other parent. That is nothing to sneeze at. The thread, though, is about her good faith effort to both satisfy the need of her children to habitually fulfill their real religious duties and their family’s need to respect the boundaries of their other parent’s custody rights.