Hey Guys please help me out here in the insurance and hospitals

I am a Software Engineer(Frontend), and currently,, I am giving interviews since the job market is tough., I am working as a freelancer.

My father has a tumour in his knee(detected in USG); the doctor has suggested an MRI and, based on that, maybe a Biopsy. Also, he has 2-3 lumps around the navel(not sure what it is as the doctor said first we will examine the knee since it is causing pain).

Please help me here with a few questions:

1. Is corporate insurance covered from day one?
2. If I join a company, will I be able to claim the insurance(the situation currently I am in)
3. What else can be done to have the insurance, If I join a corporation?
4. Is there any hidden health benefits, which I can claim against?
5. What are the best hospitals in India if it tumour turns out to be cancerous?
6. Is there any alternative way to treat this(I know if it is cancer than it's hard but still wanna know if any miracle can happen)
7. What else I can do so expenses can be covered?
8. Please share your knowledge in this regard.

Thank you, your help means a lot 🙏