I was in a rear-end car accident roughly a year ago with head trauma to the head rest.
Unfortunately, this was NOT my first head trauma experience as I had head trauma 2.5 years prior which resulted in roughly 2 years of symptoms/PCS.

The car accident brought back A LOT of symptoms. Most of which I still suffer with today.

I hired a lawyer and got some PT for my neck through an orthopedist (who claimed I had a "neck sprain").
However, I visited a neurologist a few months after the accident and his report wasn't very generous as it relates to concussion or PCS.
My lawyer claims the case for head trauma/headaches/PCS/etc isn't very strong because of that report and because I have a prior history.

Fast forward to today. I've been offered a pretty nice settlement by the other driver's insurance company (pain and suffering for the "strained neck").

I'm not really interested in money. I'm more interested in having the protection knowing I can get my medical bills recouped.
But at the same time, I'm not actively seeking treatment because I don't know who/what/where to go next.

Is it even realistic to claim PCS this far out in the game?
Or should I just sign the settlement and leave it at that?

Any advice?

The past history, is a big issue, and the fact that you are not seeking ongoing treatment.
*If you had/have a primary doctor that treated you the other time, and had his notes and that you were quite recovered... then went to him right after this new accident for treatment ... he could document the increase in symptoms.. then there would be a written record by a professional.. It helps to have a very knowledgeable dr treating you also..*

Those factors make it seem that you are not that badly injured from this recent accident..
I agree with your atty, put the pretty nice settlement money in a saving account for when you do need/find treatment.
And later when you do find some treatment/provider , you might be able to use medical ins..

It's a toss-up. Unless a doctor defines a precise treatment plan, I don't go back to them.
So, in that regard, I actually don't have a ton of medical records (~10-15 doctor visits across 2 years), since no doctor has given me any solid treatment advice for PCS.
But, as you said, I also don't have any documented "recovery" either. Of course, most doctors say to come back if symptoms don't get better. There's no reason to visit if your symptoms go away!

It's ironic, because my "soft tissue injury" was diagnosed subjectively and it's deemed a valid medical injury.
While PCS, which is also diagnosed subjectively, isn't really given the light of day by the auto insurance company (or my lawyer and neurologist).

You don't say if you have any ongoing symptoms.

"Unless a doctor defines a precise treatment plan, I don't go back to them."
This concept is like shooting yourself in the foot from a legal standpoint. This is what defense attorneys call 'refusal to cooperate with medical advice.'

It can also make it look like you are doctor shopping, again a negative to you case.

Insurance companies often have a rule of thumb settlement amount based on the type and severity of a collision and just want to get the case resolved if it is below that threshold.

As Jo*Mar said, it the settlement leaves you with cash in the bank after paying your medical bills, property damage, and attorney's fees, it may be the way to resolve this. Your attorney should have told you this but, Make sure you don't have bills that were paid by your insurance (health or auto) that your insurance company will want repaid from your settlement.

I've know people who have been charged in arrears for such payments.
My mother-in-law's car was totaled and replace by her insurance but they expect to get paid back from her settlement from the at-fault party's insurance.

I do.
EDIT: To clarify, the upper neck/lower skull issue (the reason for PT) is much better. So the "soft tissue" injury aspect has been put to bed.
My ongoing symptoms are more in-line with the similar symptoms I had after my first head trauma experience.

I totally understand that. But again, my intent wasn't to get compensation, it was to get better.
Given my prior experience with head trauma, doctors were pretty useless in defining a practical treatment plan.
There were only so many, "come back in a month if your situation doesn't improve" responses that I could tolerate.
In hindsight, I can now see that I wasn't very smart from a legal standpoint; but honestly, I wanted to get better, not build a case.
But when the attorney's own neurologist didn't diagnosis a concussion or PCS, it doesn't help my case.

It's a pretty open and shut case. Attorney gets 1/3rd of the settlement as compesation, so no fees. Plus, most of my medical bills were paid OOP since I have a HDHP and the medical providers didn't ask for payment either since my attorney attached them to the lawsuit; so he will handle most of the medical payment dispersements.

Just be clear (in writing) of what atty is doing and promised to do for you, and where /when any dispersements come from.. your percentage or his, or off the top then divided out..??

my long ago work comp claim atty , told me a lot of stuff, I'll help you do this and that etc,, but after he got his $$$, it was very hard to get anything else help wise..
Some of my PT bills came off the top of the settlement, but atty didn't list the MRI so that fell back to me to pay... after all done..