Ibn Taymiyyah did not have two opinions about declaring people to be unbelievers
19-3-2015 | IslamWeb
Question:
AslamualakaumI heard somone say ibn taymiah changed his opinon towards the end of his life, he said that anyone who says laillah ilalllah is a muslim and cant have takfeer on him, and also those who do wudu as the Prophet (pbuh) said only a muslim maintains wudu, thus those who do wudu can not be kafir.HAdith below"“Adhere to righteousness even though you will not be able to do all acts of virtue. Know that the best of your deeds is salah (prayer) and that no one maintains his ablution except a believer.” (Majah) [9]"Apparntly one of his students narrates this.What is our reply,
Answer:
All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu ‘alayhi wa sallam, is His slave and Messenger.
What we are aware of is that Shaykhul-Islam Ibn Taymiyyah 
is among the people who are very precautious about the matter of declaring people to be unbelievers. He made many statements about this; you may for instance refer to Fataawa 91677 and 135063.
He does not have two opinions about this so that it can be said that he changed his mind towards the end of his life.
If you are referring to what Ath-Thahabi quoted from him in Siyar A‘laam An-Nubalaa': “Our Shaykh Ibn Taymiyyah said toward the end of his life, I do not consider any person from this Ummah to be a disbeliever, and he said that the Prophet, sallallaahu ‘alayhi wa sallam said, "No one maintains ablution except a believer" so whoever observes the prayers with ablution is a Muslim.” [End of quote]
All what this means is that he emphasized the approach that he was following, and it cannot be understood at all that he was following another approach earlier and then changed his mind.
Allaah Knows best.