HSAs as they exist today allow a person to contribute tax deductible money (like a traditional IRA) to a savings account. The funds in the savings account can be spent tax free for qualified expenses. If the money is invested it also grows tax free. This means a discount on your cash health expenses of the amount you would have paid in taxes, which given your relative's income isn't likely to be very much.
As HSAs exist today they must be paired to a qualified High Deductible Health Plan (HDHP). Many plans have a deductible that meets or exceeds the level set by the regulations but many plans waive the deductible for things like X-Rays; waiving the deductible causes most "high deductible" plans to not qualify for HSA accounts.
There are other qualified HSA expenses like Long Term Care (LTC) insurance premiums that can also be spent tax and penalty free from HSA funds.
At age 60 with low income an HSA serves little purpose because the tax savings is so marginal and an HDHP is required. That does not however mean that the scope of HSA availability should not be expanded. Just because this is not a silver bullet for everyone does not mean it is of no use to anyone.