The advantage of the Catholic Church to all other religions is in the Sacraments of Jesus Christ.
What we share with the whole world is the Natural Law written in our hearts.
What we share with the Jews and Non Catholic Christians, are the Ten Commandments. The Law of God. Scripture says:
Acts 10:33-35
King James Version (KJV)
33Immediately therefore I sent to thee; and thou hast well done that thou art come. Now therefore are we all here present before God, to hear all things that are commanded thee of God.
34Then Peter opened his mouth, and said, Of a truth I perceive that God is no respecter of persons:
35But in every nation he that feareth him, and worketh righteousness, is accepted with him.
And also:
Revelation 22:14
Blessed are they that do his commandments, that they may have right to the tree of life, and may enter in through the gates into the city.
Therefore, the Natural Law is the salvation method common to all people.
The Ten Commandments constitute the salvation method common to all believers in the Judeo/Christian God.
However, Catholics (and the Orthodox) have maintained the Traditions of Jesus Christ, especially the Mass and the Sacraments. Although some of the Protestants have maintained the Sacrament of Baptism, they have discarded all the rest.
And it is only through the Sacraments that we enter in:
Hebrews 12:23
To the general assembly and church of the firstborn, which are written in heaven, and to God the Judge of all, and to the spirits of just men made perfect,
For it is not by any works of righteousness which we do, nay not even faith, which is a work:
John 6:28-30
King James Version (KJV)
28Then said they unto him, What shall we do, that we might work the works of God?
29Jesus answered and said unto them, This is the work of God, that ye believe on him whom he hath sent.
30They said therefore unto him, What sign shewest thou then, that we may see, and believe thee? what dost thou work?
Faith is believing and believing is a work.
No it is by the mercy of God through the washing of regeneration and the renewal of the Holy Spirit:
Titus 3:5
Not by works of righteousness which we have done, but according to his mercy he saved us, by the washing of regeneration, and renewing of the Holy Ghost;
Yes, the washing of regeneration and renewing of the Holy Ghost is an explicit description of Baptism.
But the washing of regeneration and renewing of the Holy Ghost is also an implied description of every single Sacrament. Because in all the Sacraments we are bathed in the washing of the Holy Spirit which washes away our sins as we call on the name of our Lord.
And the Sacraments therefore are the reason why you and your friend should become Catholic.
Sincerely,
De Maria