Sage Sankara claims that the world is not false. It appears false only when compared to Brahman (Consciousness).+

Rig Veda: ~ 'Prajnanam Brahma'- Consciousness is the ultimate reality or Brahman or God in truth.

Do not accept any other God other than the Soul. The Soul is God in truth,  Nothing is real but the Soul, which present in the form of consciousness. Nothing Matters but realize  God in truth. God in truth is everywhere and in everything. Let these words be inscribed in your subconscious.

God in truth is hidden by the illusory universe. God in truth alone is real and eternal and all else is an illusion. 

Brahman is merely a word to indicate the ultimate truth or God in truth.  The ultimate truth itself is God in truth. 

Remember:~

According to Advaita Vedanta, the Veda addresses itself to two kinds of audiences - the ignorant people who desire the transitory heaven and other pleasures obtained as a result of ritual sacrifices, thus, the Purva mimam. sa, with its emphasis on the karma kanda of the Vedas, is meant for the first audience, to help lead its followers along the way. Thus, all the theistic Advaita is meant for the ignorant populace.

The path of wisdom is divided into three parts:~

First:~ hearing the truth--that the consciousness is the only reality and that the universe along with you merely an illusion or Maya. 

Second:~ reasoning upon these words of wisdom of Sage Sankara from all points of view. 

Third:~ giving up all further argumentation and realizing the truth. This realization comes from being certain that consciousness is the ultimate truth or Brahman or God in truth. 

The serious seeker who is seeking truth nothing but the truth or Brahman or God the Vedanta, with its emphasis on the jnana kanda, is meant for those who wish to go beyond the form, time, and space to realize their true existence is formless, timeless and spaceless existence.

All the theistic Advaita belongs to religion it is nothing to do with Sage Sankara’s Advaitic wisdom

Sage Sankara Advaitic wisdom is purely based on soulcentric reason and independent without the support of any scriptures.

Sage Sankara:~ “This (the unreality of duality) is borne out by the Srutis ... But it is possible also to show the unreality of the objective world even from pure reasoning. (Commentary on the Manduka Upanishad, II, 1)

Sage Sankara himself had often said that his philosophy was based on Sruti, or revealed scripture. This may be because Sage Sankara addressed the ordinary man, who finds security in the idea of causality and thus in the idea of God—and Revelation is indispensable to prove the latter. He believed that those of superior intelligence, have no need for this idea of divine causality, and can, therefore, dispense with Sruti and arrive at the truth of Non-Dualism by pure reason.

Sage Sankara gave out what was of most use to the greatest number of people. Therefore, in the commentaries on the Upanishads, such as the famous Manduka, he gave the Advaitic message of the identity of Atman and Brahman, revitalizing the philosophy and practice of Advaita, while in the commentaries on the Brahmasutra he gave lesser teaching, positing both higher and lower Maya and higher and lower Brahman (Ishvara) to explain creation for those of lesser intellects until they were ready for the highest truth.

Sage Sankara says: - Whatever thing remains eternal is true, and whatever is non-eternal is untrue. Since the world is created and destroyed, it is not true.

The Truth is the unchanging thing. Since the world is changing, it is not true.

Whatever is independent of space and time is true, and whatever has space and time in itself is untrue.

Just as one sees dreams in sleep, he sees a kind of super-dream when he is waking. The world is compared to this conscious dream.

The world is believed to be a superimposition on consciousness, which is  Brahman. Superimposition cannot be true.

On the other hand, Sage Sankara claims that the world is not false. It appears false only when compared to Brahman (Consciousness). In the pragmatic state, the world is completely true—which occurs as long as we are under the influence of Maya. The world cannot be both true and false at the same time; hence Sage Sankara has classified the world as indescribable. The following points suggest that according to Sage Sankara, the world is not false. (Sage Sankara himself gave most of the arguments).:~

Santthosh Kumaar