First person who hit the deer on the freeway, is she liable for the other 2 cars who got hit by the deer?

I think it's just an unfortunate accident; probably not unless she admits she was speeding texting etc. and could have avoided the deer.

Can an MD demand a $100 "consultation fee" from a 91 y.o. patient to answer her Q's re a brand new drug he prescribed for her?

Doctors don't have to work for free but you weren't treated very well and you did agree to pay. I'd find a new doctor.

Aunt has Advance health directive for my Grandmother. Can I as a Grandson PETITION the court to retun medical to my uncle?

This seems to be more a probate than a PI question. All the best, sounds like a sticky spot.

I was working on my car at a friend's parents' house and I was under it. My friend tried to do me a favor and open the hood but

As Mr. Barnes said, this is a very complex area. Best to consult with a PI lawyer who's well versed in coverage.

For causes of action of defamation, intentional and negligent infliction of emotional distress, and intentional interference of

I'd think business/defamation/or even employment lawyers would be best for you. All the best.

It seems like you know the difference between the two. What's the issue?

What Can I Do As A Defendant?

See the other responses. The answers aren't going to change because you post the question 3x.

Lawsuit

You can certainly have a local med mal lawyer investigate. More info would be needed to comment here.

How to calculate lost wages for personal injury settlement. i am self employed and income varies monthly. (RealEstate appraiser)

YOU ARE INSANE TO BE DOING THIS WITHOUT REPRESENTATION. WHATEVER YOU TELL THE INSURANCE CO., THEY WILL LOWBALL YOU. Honestly. It doesn't matter...

Blood and headache

I think you need WebMD, friend. Yikes.