Does the statement "it's not a problem" from someone who used ill-gotten money for a good deed constitute a denial of the sanctity of money?

You must repent to Allah for taking haram money and learn how to dispose of it. The questioner's statement that "it is not a problem" does not mean that he considers this forbidden money permissible or denies its unlawfulness. To learn how to treat scrupulosity (waswasah), please refer to Fatwa No. 59951.