The Comforter is Jesus in Spirit form

What saith our Saviour? “I WILL NOT LEAVE YOU COMFORTLESS: I WILL COME TO YOU.” “He that hath my commandments, and keepeth them, he it is that loveth me: and he that loveth me shall be loved of my Father; and I will love him, and will manifest myself to him.” When trials overshadow the soul, REMEMBER THE WORDS OF CHRIST, REMEMBER THAT HE IS AN UNSEEN PRESENCE IN THE PERSON OF THE HOLY SPIRIT, and He will be the peace and comfort given you, MANIFESTING TO YOU THAT HE IS WITH YOU….—Letter 124, 1897. (Daughters of God, p. 185.2, Ellen White)

“We need to realize that the Holy Spirit, who is as much a person as God is a person, is WALKING THROUGH THESE GROUNDS, UNSEEN BY HUMAN EYES; ... HE HEARS EVERY WORD WE UTTER and knows every thought of the mind.” (E.G. White, Sermons and Talks, Vol. 2, pp. 136, 137, 1899)

So who is this "person" who is "WALKING THROUGH THESE GROUNDS, UNSEEN BY HUMAN EYES," and who "HEARS EVERY WORD WE UTTER?"

“CHRIST WALKS UNSEEN THROUGH OUR STREETS. With messages of mercy He comes to our homes.” (E.G. White, Ministry of Healing, p. 107)

“How few realize that JESUS, UNSEEN, IS WALKING BY THEIR SIDE! How ashamed many would be to hear His voice speaking to them, and to know that HE HEARD ALL THEIR FOOLISH, COMMON TALK!” (E.G. White, Manuscript Releases, Vol. 14, p. 125.3)

“Remember that JESUS IS BESIDE YOU WHEREVER YOU GO, noting your actions and LISTENING TO YOUR WORDS.” (E.G. White, The Youth Instructor, Feb. 4, 1897)

“We want the HOLY SPIRIT, which is JESUS CHRIST.” (E.G. White, Letter 66, April 10, 1894)

“But it is the leaven of the SPIRIT of JESUS CHRIST, which is sent down from heaven, called the HOLY GHOST, and that Spirit affects the heart and the character.” (E.G. White, Manuscript 36-1891)

“The HOLY SPIRIT is the SPIRIT of CHRIST, which is sent to all men to give them sufficiency.” (E.G. White, Manuscript Releases, Vol. 14, p. 84.3)

“The human agent, the seen instrument, is to preach the Word, and the LORD JESUS, THE UNSEEN AGENCY, BY HIS HOLY SPIRIT is to make the Word efficacious and powerful.—Letter 105, 1900.” (E.G. White, Selected Messages, Book 2, p. 18.3)

The comforter that Jesus prayed for his Father to send would be the same Jesus in a none bodily form, so by this Spirit form he could be with them, all at once.

The Spirit operates on the internal invisible level, representing God and his Son in a non-bodily form.