I would look at what drove them away and whether they will attend church and participate in the life of The Church or not. If crossing over means that they will spiritually come back to life, I would be happy. Indifference would be concern if they left The Church for some Protestant sect.
As it is, in the Orthodox Church, their souls will continue to receive sacraments and the Eucharist, make signs of the cross, worship the Holy Trinity, atted a 1600 year-old litugry that even Latin used to serve at one time, commmorate the dead, fast nearly six months of the year, baptize their infants, magnify and venerate the Ever-Virgin Mother of God, and other Saints, and live a life based on the Holy Tradition.
What exactly have they lost that should be of concern?
However, were I in Rod's position, I don't think I'd have switched over from the Catholic to the Orthodox Church, for various reasons: (1) I think the papacy is both true, and a practical asset; (2) I couldn't go from a church that explicitly rejects divorce/remarriage and contraception, to one that doesn't; and (3) though nothing shakes my faith more than the amazing success of evil --- and Rod was exposed to toxic doses of corruption in way-high places when he was investigating the clerical exploitation of minors --- it just seems that there's noplace you can go to get away from the broken human condition.
For whatever set of intellectual and emotional reasons, Dreher couldn't pray in his parish anymore. He (and his wife) would come away troubled or angry or upset; and they didn't want to raise their kids that way.
So they found a place where they could pray.
If --- IF --- that's an accurate take on the situation, then I say to brother Rod, "Go pray with the Orthodox, and God bless you." A wise priest once said to me, "Pray as you can, not as you can't." I guess that goes for all the rest of us, too.
I'll be Catholic til the day I die; and then, relying on God's mercy, we Catholic and Orthodox will meet merrily together in heaven. And many others, too --- since God has a mighty, mighty will to save: Savior is His name.
What good is it for someone mired in serious sin to receive the sacraments?
Rod clearly has some major issues with taking scandal and other serious sins.