How to clear sand devil the way, that it was intended?

Hi guys I know that every boss has mechanics that you have to play around to beat it eg, Ice golem hard has to be burnt, fire knight has to be frozen etc. How do you handle the sand devil with sleep? I can put him to sleep, place debuffs and stuff and still get one shot after these 7 hits he get. I managed to brute force him till stage 15, but after that i need to play aroung his mechanics, and I cannot figure it out. How do you do that, without gnuting it out or using aniri (i dont have her)?