This is not really a car accident or personal injury question. That being said, I think you would have a tough time proving that your son was treated the way he was treated because of his tattoos or ethnicity as opposed to his lack of health insurance...not having health insurance is an excellent way to not be able to get medical treatment in this country.
You can sue for discrimination, but unless you have damages, you have nothing to "win" through litigation. Further, it appears if there was any discrimination it was because of financial status, rather than race or appearance. Financial status is not a protected class, and neither is appearance. It does not sound like your son in law was denied services based on his race. And any service provider has the right to expect to be paid at the time services are rendered. Your son in law should follow up through police reporting to see if there is any victim's assistance funding available to help with his medical expenses, and should make a claim with his own vehicle insurance company to see if he has any medical payments coverage or uninsured motorist coverage.
Responses are for general information purposes only, and are based on the extremely limited facts given. A consultation with an attorney experienced in the area of law(s) indicated in the question is highly recommended. Information and advice given here should not be relied upon for any final action or decision, as the information is limited by its nature to the question asked and the fact(s) presented in that question. THIS RESPONSE DOES NOT CREATE AN ATTORNEY/CLIENT RELATIONSHIP, particularly considering that the names of the parties are unknown.
Your son has a potential claim for uninsured motorist benefits and should consult with an attorney right away. The discrimination issues can be discussed as well.
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