Author says:

Nevertheless, they have concocted a story that the Imam called for a wedding ceremony on this day, declaring, 'It is my wish to see one of my daughter wedded to Qasim.' Obviously, one cannot take one's wishes to one's grave.

According to Hajji Nuri, Mulla Husayn Kashifi was the first man to write this story in a book named Rawdat al-shuhada' and it is totally fictitious.

Here a mere claim is made without any proof and supporting evidence that since the incidence of the marriage of Qasim ibn Hasan (as) was first quoted in the book "Rawdat Al-Shuhada" hence its a fabrication.

The writer has completely ignored the fact that many scholars have quoted this incidence in their book. Below is what is quoted in our books:

فمسك الحسين عليه السلام على يد القاسم وادخله الخيمة، وطلب عونا وعباسا وقال لام القاسم: (ليس للقاسم ثياب جدد ؟). قالت: لا. فقال لاخته زينب (ايتيني بالصندوق) فأتته به ووضع بين يديه ففتحه واخرج منه قباء الحسن عليه السلام وألبسه القاسم، ولف على رأسه عمامة الحسن، ومسك بيد ابنته التي كانت مسماة للقاسم، فعقد له عليها وافرد له خيمة، وأخذ بيد البنت ووضعها بيد القاسم وخرج عنهما

"Then Imam Husain (as) grasped the hand of Qasim (as) and entered him into the tent, and called Own (as) and Abbas (as). And said to Qasim's (as) mother: "Don't we have for Qasim (as) any new clothes?" She said: No.

Then Imam Husain (as) told his sister Zaynab (sa), "Bring me the case. Then took it and opened it and brought Imam Hassan's (as) cloth out of it, and dressed it on Qasim (as , and wrapped the Amamah of Imam Hasan (as) on Qasim's (as) head. And took the hand of that daughter of his who was named for Qasim (to be married to Qasim), then performed her Aqd to him, and emptied the tent from others and put the hand of his daughter in the hand of Qasim (as) and he went out himself."

[Source: Madinat-ul-Ma'ajiz, Vol.3, Pg. 368 / Wafiyat Al-Aaimmah Pg. 128]

Whether this incident is true or false can always be debated and further researched. But If this is still a fabrication then its surely a fabrication from scholars who have quoted this in their books.