I pondered it too before I posted it because it sounded too much like going ahead with an abortion if the mother’s life was in danger. But that doesn’t quite fit the section you highlighted.
How about — staying home from Church on Sunday because you are taking care of a sick relative? Weak Relative, Dying Relative? New mother who suddenly started hemmoraghing?
Your second paragraph seems reasonable. Staying home from Mass to take care of a family member, say, even if the family member told you he’s fine and you should go to Mass, because the “weak” might think you’re not acting as they imagine a Christian should.