Totally valid. Concern for individuals is a very real argument.

Your friend's parents should have moved legally. The reasoning for many people holding this stance is that it is not the countries the illegal immigrants came from or just the people wanting to support them that float the bill for their care. It is the burden of every tax paying citizen.

Imagine an organization that did something you don't agree with and forced you to pay for it. A reasonable person would say "why don't the people who support this organization fund it themselves". It is a fair point of view.

The widowed mother point is a very complicated issue. Healthcare costs in the US are ridiculously high because they are funded by taxes and insurance. It is an absolutely necessary service to all individuals, no exceptions. If someone were told "we have to pay what you ask for" the person performing the service will inflate the price beyond any reason. That is why medicaid and insurance is inherently broken in its current state.

Environmental regulations are similar. Prices go up on goods and labor and wages are decreased because of regulatory bodies being in the same boat as the service provider above. If a company pollutes, it should be boycotted instead. If their are no better options, then better options should be established to force the company to compete by being green. Otherwise mid and low level industry is almost forced to not exist. Because strict regulations allow companies that can pay the fine to exist, but potentially green alternatives to be under boot and unable to pay.

Always remember the three axioms of government. It does not produce, it does not control, and it does not molest. If you feel or think a policy or action is right/wrong for a government run it through the test.