One of the amazing things about the gospel is the ability for us to united with our families for eternity. God wants all of His children united, from the beginning with Adam and Eve, all the way to your descendants.
With this unity, it can come with the feeling that everything must be perfect in this life. While sometimes we love people very much, they still choose to move away from the gospel. Especially with how confusing it can be in this technology enabled world. The Lord's hand is extended still to them. They will have the oportunity to return unto the fold. Much like the prodigal son. Whether in this life or the next.
While everyone does have their own agency. It is easy to forget that they may choose differently than us. What we must rememeber, much like missionaries out in the field is that we are only able to bring the message to their hearts. It is up to them to accept it into their hearts.
As we do everything we can, we are able to remember that whatever happens. The gospel and temple sealing unite us. This is expecially important for those that have lost children and did not have a chance to raise them in this life. This is not the end, but the beginning.