You need a personal injury attorney to represent your interests. Your post lacks details including the elements of injury and medical claims which would indicate potential damages to which he may be entitled. You should seek TX counsel as soon as possible.
You might find my Legal Guide helpful "How to Choose A Lawyer For You"
Check with a lawyer in your locale to discuss more of the details.
Good luck to you.
You might find my Legal Guide helpful Successful Start for a Personal Injury Lawsuit
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You need to hire a qualified personal injury lawyer immediately. Whether or not the responsible party is deceased, his estate may liable and unless you assert a timely claim, you will be waiving your right to sue for damages. Every moment that you delay is more time for evidence to be lost and assets to be removed from the responsible person's estate. Worker's comp will end and how do you know if you are getting a fair amount. It may also preclude any recovery later. There are a lot of issues that you cannot factor in without knowing the law. I would strongly suggest you contact a personal injury lawyer in your area to make sure your rights are protected.
I'm afraid that if there is any money legally available to you, the chances of it being spent before you ask for your due portion go up every second. I'd hire an attorney right now.