Since Murids of the Tijani Tariqa should only read books covering general sufism and avoid Tariqa specific sufism, would the recently released "The Drink of the People of Purity" by Shaykh Muhammad al-Qandusi count as the former or the latter!
As-salām ᶜalaykum wa raḥmatu’llāh!
al-Ḥamduli'llāh, may Allāh ﷻ give success to His creation in drawing them closer to Himself. Actions are but by their intentions, and the better decision is to steer clear of that which could be harmful to the spiritually sensitive matters of one’s journeying to Allāh ﷻ. For the sake of serious consistency in one’s relationship with Shaykh al-Tijānī and to avoid the dangers of seeking spiritual assistance from outside the Path, it is discouraged for the aspirant to visit non-Tijānī saints and spiritual masters outside of this Path for that intent.
As far as books are concerned, and specifically this potentially beneficial text by the renowned Shaykh Muḥammad al-Qandūsī (may Allāh ﷻ have mercy on him), I humbly suggest that you defer the matter to your guiding teacher or initiator (muqaddam) to vet the book and deem its appropriateness for you, inshā'llāh. There is safety in asking questions and seeking support from within your own house.
Thank you kindly for your question, and may Allāh ﷻ accept our best intentions. He knows best, always and all ways.