Well an easy way for you to determine whether this is true or not is to ask the person who said it to bring his proof.
For everything in the religion of Islam there has to be proof in the form of an hadith or an ayah from the Qur'an.
So ask this person where does it say in the Qur'an or hadith that you should do this?
it's important you ask for proof otherwise any tom dick and harry can come upto you and say " if you do this then you get this much reward"
so whenever some 1 tells you something that is from Islam ask them where it says in the Qur'an and hadith, if it's not in them 2 sources then they're just making it up and it becomes an innovation.
but to answer your question, I've read that the dying person should read the kalma shahada just before he dies but never heard of the number 1000.