Here's a few you can show him:
*** Insight, Vol 2 p. 362 Mediator
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Those for Whom Christ Is Mediator. The apostle Paul declares that there is "one mediator between God and men, a man, Christ Jesus, who gave himself a corresponding ransom for all"—for both Jews and Gentiles. (1Ti 2:5, 6) He mediates the new covenant between God and those taken into the new covenant, the congregation of spiritual Israel . (Heb 8:10-13; 12:24; Eph 5:25-27) Christ became Mediator in order that the ones called "might receive the promise of the everlasting inheritance" (Heb 9:15); he assists, not the angels, but "Abraham’s seed." (Heb 2:16) He assists those who are to be brought into the new covenant to be ‘adopted’ into Jehovah’s household of spiritual sons; these eventually will be in heaven as Christ’s brothers, becoming a part with him of the seed of Abraham. (Ro 8:15-17, 23-25; Ga 3:29) He has transmitted to them the promised holy spirit, with which spirit they are sealed and are given a token of what is to come, their heavenly inheritance. (2Co 5:5; Eph 1:13, 14) The total number of those who are finally and permanently sealed is revealed in Revelation 7:4-8 as 144,000 .......................................Blessings to Mankind in General. While Jesus’ mediatorship operates solely toward those in the new covenant , he is also God’s High Priest and the Seed of Abraham.
Insight Vol-2p. 858 Sanctification
However, Moses as God’s appointed mediator could draw nearer. In this, Moses prophetically foreshadowed
Jesus Christ, the great Mediator for anointed Christians , as they approach heavenly Mount Zion.—Heb 12:22-24.
w79 11/15 p. 24 par. 12 Benefiting from "One Mediator Between God and Men"
So
Jesus Christ in heaven is the Mediator between God and the spiritual Israelites, while these are still in the flesh as men and women............... ....................Today....there is a "
great crowd " of dedicated, baptized Christians who actively collaborate with the small remnant of spiritual Israelites. Ever since the spring of 1938 they have been invited to attend the annual memorial celebration of Christ’s death, not to partake of the memorial emblems, the unleavened bread and the red wine, but as respectful observers.......
They recognize that they are not spiritual Israelites in the new covenant mediated by Jesus Christ, nor part of the "chosen race, a royal priesthood, a holy nation." —1 Pet. 2:9.
w89 8/15 p.31 Questions From Readers
The people of all nations who have the hope of everlasting life on earth benefit even now from Jesus’ services. Though he is not their legal Mediator, for they are not in the new covenant , he is their means of approaching Jehovah. Christ said: "I am the way and the truth and the life. No one comes to the Father except through me." (John 14:6) All who will gain life on earth must direct their prayers to Jehovah through Jesus. (John 14:13, 23, 24) Jesus also serves as a compassionate High Priest who is able to apply in their behalf the benefits of his sacrifice, allowing them to gain forgiveness and eventual salvation.—Acts 4:12; Hebrews 4:15.
Consequently, 1 Timothy 2:5, 6 is not using "mediator" in the broad sense common in many languages.
It is not saying that Jesus is a mediator between God and all mankind. Rather, it refers to Christ as legal Mediator (or, "attorney") of the new covenant, this being the restricted way in which the Bible uses the term. Jesus is also a corresponding ransom for all in that covenant, both Jews and Gentiles, who will receive immortal life in heaven. The apostle John referred to these at 1 John 2:2. But he indicated that others too will receive the benefit of Christ’s sacrifice: "He is a propitiatory sacrifice for our sins, yet not for ours only but also for the whole world’s."
Questions From Readers
Is Jesus the "mediator" only for anointed Christians?
The term "mediator" occurs just six times in the Christian Greek Scriptures and Scripturally is always used regarding a formal covenant.
Moses was the "mediator" of the Law covenant made between God and the nation of Israel. (Gal. 3:19, 20) Christ, though, is the "mediator of a new covenant" between Jehovah and spiritual Israel, the "Israel of God" that will serve as kings and priests in heaven with Jesus. (Heb. 8:6; 9:15; 12:24; Gal. 6:16) At a time when God was selecting those to be taken into that new covenant, the apostle Paul wrote that Christ was the "one mediator between God and men." (1 Tim. 2:5) Reasonably Paul was here using the word "mediator" in the same way he did the other five times, which occurred before the writing of 1 Timothy 2:5, referring to those then being taken into the new covenant for which Christ is "mediator." So in this strict Biblical sense Jesus is the "mediator" only for anointed Christians.
The new covenant will terminate with the glorification of the remnant who are today in that covenant mediated by Christ. The "great crowd" of "other sheep" that is forming today is not in that new covenant. However, by their associating with the "little flock" of those yet in that covenant they come under benefits that flow from that new covenant. During the millennium Jesus Christ will be their king, high priest and judge. For more detailed information, see AidtoBibleUnderstanding, pages 1129 and 1130 under "Mediator"; also God’s"EternalPurpose"NowTriumphingforMan’sGood, page 160, paragraph 10; also TheWatchtower issues of February 15, 1966, pages 105 through 123; November 15, 1972, pages 685 and 686, under the subheading "Leading the Way to a New Covenant"; and April 1, 1973, pages 198 and 199, under the subheading "The New Covenant."