Rocky, what's your relationship to this widower? Do you know what illnesses her husband had, and what kind of insurance, especially any supplemental insurance? There can be a wide gap between what some supplementals pay and what an alternative plan might pay.
If she was on Medicare, they send out quarterly statements. If she had a supplemental insurance, contact the insurance company If she was on Medicaid look at the Medicaid statements. Some doctors do not accept Medicaid, so you pay.
Google "medical bill review" or "hospital bill review" to find companies that review bills for errors and overcharges for a fee. Apparently overcharges are very common, and sometimes people just pay them instead of challenging the charges.
If she had a supplemental insurance, contact the insurance company
If she was on Medicaid look at the Medicaid statements.
Some doctors do not accept Medicaid, so you pay.