Seniors are only a percentage of the population.
The morality is in the choice in life and death. (there isnt a lot of morality in becoming wet or not wet) The rain falling is not farily comparable to having to obtain debt or not choose treatment. If you use the same thought is it moral to not shield someone from deadly acid rain? Before we land back at the train problem again, dont you think it is strange how the vast majority western world does have a universal healthcare system. You have the choice to keep the status quo or vote for reform in healthcare.
You appear to be attempting a false dichotomy (albeit carefully). You're strongly insinuating that the choice is between status quo or socialized healthcare, and that is not correct.
I don't know why you keep harping on debt, as though it is somehow different from not debt but bankruptcy, or just a decrease in resources, or even not being able to obtain the debt and having to forgo treatment. You seem to have a special place in your heart for debt, and I'm not sure why.
We all make personal decisions about our lives, our quality of life, our finances, and our level of care. And these decisions are necessarily made by someone, it's not moral to remove that decision from the individual, and make it at a political level. Here's a concrete example.
No universal healthcare or insurance:
Bob earns (or doesn't earn) money.
Bob needs knee surgery.
Bob's knee surgery will cost $20,000.
Bob must choose between getting knee surgery or keeping his $20,000 (regardless of whether he has the money).
Universal healthcare:
Bob votes for the government to seize money from others for healthcare.
Bob needs knee surgery.
Bob's knee surgery will cost $20,000.
The government must choose whether Bob gets his knee surgery, or the seized $20,000 is spent on another patient.
You can see how the decision is still made, and how it is Bob's decision to make. You can also see the immoral choice to seize assets from some people and give it to another. You're framing the moral scenario as immoral (despite a lack of immoral actor), and framing the immoral scenario as moral (despite at least two immoral actors).
Edit:
BTW, I recall donating to someone
in the UK (where presumably socialized healthcare is a thing) who needed a wheelchair and was having trouble raising the money. And no it was not fraud.