Tim Challies gives some good encouragement here regarding family worship:
There is no good way to measure the success of family devotions except by this: Did we do it? The thing is, we are building for the long-term here, not the short-term. A single episode of family devotions can so easily seem like a complete waste. But I am confident that when we measure by the hundreds spread over the 20 years the children are in our care, we will see that God worked powerfully in the hearts of our children and their parents.
Family worship doesn’t save; only Jesus can do that. But over time, God can be gracious enough to use it to awaken the gospel in the next generation.
You can read the whole post here.