Guru is not any physical body or identified name of a person. The cosmic energy of the universe takes various physical forms (Sakara) and metaphysical forms (Nirakara) both such as, it also created various Tatwas, and these Tatawas are responsible for creation, preservation, and destruction in this universe.
Guru Tatwa is one of these that was, it is also known as Guru Shakti. The physical body of the Guru is just the medium or energy channel through which this majestic infinite energy of the cosmos known as Guru Shakti flows.
This energy when enters the body of the disciple at the time of initiation, by the blessing of the Guru or being in accompaniment with the Guru or by the grace of remembering or intuitiveness of the Guru, then this energy directs you from outer to inner being or towards the Absolute being and Absolute truth of existence through raising and triggering your dormant and potential energy (kundalini Shakti). There is no other way one can move towards the Absolute without this energy guiding and securing the aspirant or disciple.
The physical body of the guru is just as ordinary as others this is not immortal but the energy, the realization, the wisdom and the Tatwa that flows through the Guru’s body is eternal and immortal and is equal to the infinite energy of the universe itself.
In simple words "Gu means ignorance, and Ru means dispeller," the immortal and eternal energy thus moves a disciple from dark to light, from mortality to immortality, and from ignorance to wisdom by burring all ignorance and illusions (Maya) that one accumulates life after life karmic debris.
So never judge a Guru by the physical body, nor ever discriminate between Guru. Never compare two Gurus, as all Gurus who have attained the Brahman or Absolute truth are all one energy and one Guru Tatwa or Guru Shakti and thus, the infinite energy flows through them.
When we talk about Sadguru remember, that it is not a term or identifying a particular personality but, it’s an ideology that is SAD or SATT means Absolute or Brahman or Truth, and Guru means the transformer of ignorance to wisdom. Now it is clear that he who has realized the absolute and through whom the Guru Tatwa flows and guides the disciple to the Absolute Truth is known as Sadguru.
A Sadguru never expects any mundane baggage from you by any means. The virtue of the Sadguru is that he always wishes and blesses you. The Guru feels happy when you progress in your spiritual practice, develop yourself and elevate to receive higher levels of spiritual practice by which your illusion (Mayas) will be dissolved so you that you can reach the core of your infinite existence.
The Guru always guards you, secures you, unconditionally loves you, and cares for your real being. Sadguru and Sadsisha with enormous trust and faith and surrender assimilate in one another and there remains no difference between Guru and disciple and this is what we refer to SAT CHIT ANANDA or infinite bliss.
To attain such an immense state, where the nectar is ever flowing, you must always have unquestionable faith, trust love respect, care, preservation, and patience, and above all, you must completely surrender yourself to your Sadguru. This is the only known way to Absolute bliss and truth.
WHY A GURU IS CALLED A FATHER AND THE GURU'S WIFE REFERRED TO AS A MOTHER?
The Guru is referred to as a father because they play a similar role to that of a biological father. Just as a father provides guidance, support, and protection to his children, a Guru does the same for their disciples. They act as a spiritual mentor, providing knowledge, and wisdom, and leading them on a spiritual path.
Similarly, the wife of the Guru is referred to as a mother because she assumes a nurturing and supportive role. She takes care of the spiritual family, comforts and guides the disciples, and provides love and warmth within the Guru's ashram or spiritual community.
These parental titles of father and mother are used to signify the deep and intimate bond that exists between the Guru, their wife, and the disciples. It reflects the love, respect, and trust that is nurtured within a spiritual family.
In terms of Yogic evaluation and concept, Guru is the father of the male gender which means he is the Purusha which signifies him to be the Shiva, everybody has the same guru is Shiva himself who is the Adi Yogi and others are called Ritwik guru (working as per the order of Shivas wish) Shiva himself is a form of formless, that is depicted as SHIVOHUM a higher understanding of HUMSO or SOHUM order. Shiva according to our Veda and Mahanirvan Tantra is the Adi Guru or Guru Shakti or Guru Tatwaa.
Mother is feminine gender it can be a biological mother; the universal operating force or energy and the same energy is in the form of Kundalini shakti at your bottom chakra (Muladhara) in a dormant state until awakened by yogic practice or will of divinity or by the grace of Guru.
Now as a child is born by a male and female biological interaction – the fluid that mixes to form the zygote forming the embryo is the kundalini shakti itself but flown outside the body downstream below the Muladhara chakra – therefore a child is born respectively a father and mother are identified is 3rd dimension or physical aspect of existence.
When this shakti rises from Muladhara chakra piercing and perforating all the upper chakras and reaches the top Sahasra we get the wisdom within the BRAMHA GYAN that means the holy union of Shiva and Shakti this also gives birth to the NEW YOU, the new you is the TRUE ABSOLUTE YOU there is nothing beyond that new you. Here also a birth is there that is significant but in metaphysical aspect at the 5th dimension of life.
Guru and Guru's ma are just outward representations of this Shiva and Shakti. Shiva or Shakti is absolute form so it is itself the Bramha. So, we understand the guru as Bramha itself.
This is just not a statement if you have found your true guru who has realized the truth can in a moment or blink of eyes make you see that, but it does not counterpart Mokhsa until karma is nullified and is zero.
Biological parents give you birth to this world and trend you in the illusion of Maya, but Guru and Guru Ma are your parents who break this chain of Maya and illusion and unify you to the supreme of your true self, your absolute nature. So, though the guru has a body the understanding is guru is just not a biological body it's beyond everything in this conscious existence of the universe.