You’re not being a model of Christianity yourself, here. If your family experienced the tragic death of a young child, would you react positively or negatively to someone outside of your church using that occasion to mock and condemn that church? I take issue with some of their theology myself, but the only decent reaction would be to pray for them. You should try that instead. Just a suggestion.
Do they know me? Do I know them? Are they reading this thread?
If a family member is on this thread I will apologize profusely. Are they on this thread?