The recovery will be yours. Your attorney knows (or should) how to handle this.

Can I sue?

Sorry, but you will get the same result (probably with more work and expense) going against the other person. Do you have gap insurance?

When will the adjuster make an offer after receiving a demand package?

Maybe today, maybe tomorrow, maybe never. Sorry, but there is no legal requirement to offer money.

What i need to do

Bring him to the doctor, then contact local/qualified counsel. Do not speak with Walmart.

How do I determine if the settlement offer from the at-fault driver's insurance company is fair?

Query, do you see the problem. "How do I determine". The fact that you don't know, is reason enough to get a professional.

Can I sue two lawyers for lying to me and dropping my case and causing so much stress to point of suicide

Yes, you have the right to sue anyone. However, it is unclear if you have the basis for a viable case. Sorry.

Legal rights when hit by law enforcement

Be mindful of short and exacting filing requirements. Good luck.

You should re-post in a different practice area. Perhaps administrative law.

Is this a homerun case for a lawsiut??

You've received expert legal advise. Follow through. Very sorry for your loss.

Do I have a malpractice case ?

Quite candidly, you can't get better advise then you did from Doc Shah.