Hello dear friend,
First of all, I am sorry for the late reply but I am a little busy currently.
Indeed, the role of the Sponsor (Godparent) in Orthodoxy is really important and it lasts a lifetime. All those who support that his/her role is not serious are misinformed about the teachings of the Orthodox Church concerning it.
Since the introduction of infant Baptism, the Godparent has assumed the important obligation, together with the parents, of ensuring that the infant is brought up within the Orthodox Church and in the life of Christ. It is precisely on account of this obligation that the baptismal sponsor is called the ‘parent-in-God’. The task of steering a child along the narrow path, and bringing them up according to the law of God is perhaps the greatest of all things in life.
St. Theophan the Recluse says that there is no holier act:
While it is an honor to be asked to be a godparent, one should make sure that the potential sponsor will be committed to the responsibility. The role must be honored and not taken lightly. Every godparent will be accountable to God as to whether or not he or she has fulfilled their duties. Prospective godparents must know their faith, or at least be in the process of learning their faith and be committed to a life in Christ. One problem today is that people who are called upon to be godparents do not know their faith and are not regular participants in the life of the Church. This is also true for some parents. Consequently a child who is baptized may never know anything about Jesus Christ and the Church. In the early Church heavy emphasis was placed on the educating of the faithful and those who desired to come into the Christian faith. As Christianity spread in a pagan world, the need to teach individuals before their baptisms became crucial. The systematic instruction, which was a preparatory stage for baptism was and is called “catechism.
You can find out more about the important role of the Godparents in the following links:
I hope it helps. God bless you.