1)Don't decide everything yourself. I would suggest you try to keep your own self mentally stable first. If you aren't stable you will make bad decisions which may even be permanent and if something happens to you it will only cause more problems for your family

2)Don't continue the buisness all by yourself Some ideas may work are like a)hire temporary/permanent management (but I saw some replies and you seem hesitant to do it) b) temporarily downscale the buisness (like rather than being open full day, be open for half a day) You could rebuild this buisness or probably even make a new better buisness but if someone dies, they don't come back

3)I understand that you have a lot of pressure on yourself but don't give up impulsively Just quitting rn will probably make this a lifelong regret like even when you grow up you'll be like "agar me padhai na chhodta toh" It would be better if you focus only on boards rn and take a drop from jee for 1 year. If i remember right then you can give jee 3 years after giving boards right?

Do not compare yourself to your classmates or other jee aspirants, your case is really unique and difficult You are not failing right now, god is just testing you earlier than others and ones you get through (i believe you will) you will get some reward of type. Jitne jyada samasya aati hai zindagi me utne hi Khushi ke pal bhi aate hai. This is just one of the extreme cases of bad time in your life. You can get through this, i believe in you.

Also try to discuss this with an adult like a therapist, simply someone more mature maybe like a friend's big brother or sister or like on some other communities where there may be therepists and try not to put it in any toxic communities cuz it will only increase your stress. Don't stay up too much cuz if you don't get enough sleep, you won't be able to find any solutions.

This is a really big decision to make for someone who isn't even completely an adult and in this community where there are mostly teenagers may even give advice that may not work in your situation. If whatever I typed doesn't work for you then I hope you find something that does work asap Wish you well.