 as for his saying so he fell down easily it means he fell down like a sick person who has fallen asleep. it is said he fell down on someone meaning he was stuck to him.
أما قوله فلبط سهل فيعني صرع ساقطا كالمريض المسبت. يقال لبط بفلان لبطا وهو ملبوط به.