How can I convince my parents that I cannot study without NEET coaching?
You only can make them understand regarding this thing. Try to tell them all about risk and benifits . If there is a financial issue then you can go for online coaching that is not that costly like offline coaching, but ofcourse offline coaching is better then the online one. You can get online coaching within 15000
Or may be less but for offline coaching you need hostel plus institution so it goes around 1-2 lakhs per year so you can talk to them regarding this they will surely listen to you.
Try to talk to them regarding your studies and dream they will surely listen to you.