Where do you find reviews?  I can't even find the publisher.  Is there an imprimatur?
There is a Last Hours book series, did you possibly read the reviews for it?

The Church provides:

Apostolic Pardon at the Point of Death



The Apostolic Pardon is a prayer usually said by the priest for  dying person and is often done in conjunction with Viaticuм.
It may take one of two forms:

1. "Through the holy mysteries of our redemption may Almighty God release you from all punishments in this life and the life to come.
    May He open to you the gates of paradise and welcome you into everlasting joy."

2. "By the authority which the Apostolic See has given me, I grant you a full pardon and the remission of all your sins
    in the name of the Father, and the Son and of the Holy Ghost." Amen.

The Handbook of Indulgences #28 states: "Priests who minister the sacraments to the Christian faithful who are in a life-and-death situation should not neglect to impart them the apostotlic blessing, with its attached indulgence.

But if a priest cannot be present, Holy Mother Church lovingly grants such persons who are rightly disposed a plenary indulgence to be obtained in articulo mortis at the approach of death, provided they regularly prayed in some way during their lifetime.  The use of a Crucifix or a cross is recommended in obtaining this plenary indulgence.  In such a situation the three usual conditions required in order to gain a plenary indulgence are substituted for by the condition "provided they regularly prayed in some way."

The reason for Last Hours, was that after sitting with a dying friend for days, with no prayerbook at hand that had appropriate prayers for just that occasion, it was thought to pull together all the prayers for the sick and dying from the Raccolta and other Catholic prayer books having an Imprimatur.  The prayers in this book all have an imprimatur as they come from a Raccolta or prayerbook having an imprimatur.  The people who have used the book have told us personally that it was a God-send for them.  That is was gold.  We have been personally given these kind of reviews.  The book not only gave great relief to the patient, but those praying with them were affected in a holy manner by the prayers and sentiments it contained.  It was put together for the purpose of readying the soul to meet its Maker - but it is also hoped to be salvific for whoever uses or reads it.  St. Joseph was prayed to while putting it together, and it was dedicated to him.  This is not a money-maker.  There are not tons of copies.  But it is useful perhaps particularly now, with people stranded without priests, or even for people who do not know what to do when sickness or death comes - this seems to give guidance.  It seemed the thing to do to let people to know it was out there.