Most anytime someone hits the point to ponder if they need counsel, the answer is yes, you do.
If that point comes after being cuffed and placed in the back of a police car, the answer is still very much yes, you do.
I am deeply sorrowful for your loss. Please know there are numerous attorneys in the greater Tulsa area, and outside the area as well, who provide legal assistance to surviving parents in such wrongful death proceedings.
You may use the Find a Lawyer feature here, or use other means of your choosing.
Unless the driver has significant assets you can pursue, unlikely in general terms but possible, your recovery will be constrained to the limit amount of his insurance policy, plus any coverage you may have under your policy regarding medical payment coverage or under insured motorist coverage or your health insurance coverage.
What a claim is worth is what it is worth. However, if the appropriate value of a claim is, just as an example, 130,000 but the policy limit is 50,000, the most the insurer can offer as a settlement is the policy limit. It is then on the injured party and counsel to decide if there is merit to instead pursue assets of the at fault person instead of settling, and any other avenues of recovery that may exist.
Sadly, sometimes there is a lot of need, and not near enough available funding...
You clearly have means to retain counsel. You indicate you have not yet been sued, but anticipate you might. with respect, why are you fussing around on an internet forum instead of sitting across from counsel signing your representation agreement? Or would you prefer to just wait for a summons and then try to deal with all your various possibilities after there are orders in place limiting what you may do?
Delay in hiring counsel is not your friend, not in the least.
People with significant assets to protect generally do not roll the road on a 25 limit policy. It's possible, but it is quite unlikely. Putting someone on a payment plan sounds good on the surface, but in reality, how will you enforce it. It is not significantly more expensive for them to have purchased a higher level of insurance protection, yet they did not. Odds are, sad to say, rather high they are not current on all existing payment plans, even for the basics.
You likely feel this isn'...
If it was a brutally cold day, this would have happened months ago. if you do not trust your counsel over this or for other reasons, sit down with counsel and either resolve the concerns or find new counsel if you find the concerns are not fully resolved.
Before discharging counsel, be certain you will not harm your proceedings by taking that action. There is nothing to gain in harming yourself or your case to make a point.