but I can't leave my job for 3 months (I know I may not get accepted, but I need to think ahead) between June and August(I have a big family to support, and i need my "ok" salary to support daily life). I am willing to give up some % of my company for free Y combinator advice.
What can I do? Is it possible ? What options can I have?
Your family's welfare has to come first- Not only is there the loss of income to think about, but health insurance.
Instead, I'd suggest spending the next 6 months living below your means, and putting the money aside. You don't need much, but enough to comfortably live on for a few months, supporting your family.
Price out private health insurance- This is cheaper in regulated states such as Massachusetts, but your situation and location will vary.
After you have a few months salary put aside, then you'll be in a stronger position to take time away from a job to start a company.