Many, many people have claimed benefits. (Can you still claim unemployment benefit if you have just left uni and live at home with your well heeled parents?) That is not the same as relying on benefits. I don't think IDS (along with many other politicians) even has to rely on his parliamentary salary to fund his lifestyle.
I am sure that IDS would be able to survive on £53 a week, as he would also, if push came to shove, be able to bake a cake or jump from a 7.5m diving board.
Would he, however, be prepared to pull all funding from his children's education (not sure how old they are), make them live in a damp house on an estate with high crime rates, stop all extra curricular activities and call a halt to Christmas, birthday presents and holidays? (Also taking into account that funding has been pulled from libraries, free swimming etc.) I wouldn't expect him to, after all he is just a politician, not Gandhi.
However, I also think he doesn't really know what he is talking about.