Is what the mother mentioned true, regarding acquiring sins similar to those of an unveiled friend who wears tight clothing when going out with her, and what is the way to deal with this friendship?

Obedience to the mother is obligatory. A Muslim is influenced by their companion, especially if they love them intensely. Furthermore, accompanying a woman who displays her adornments (mutabarrijah) makes you a target for fools and wolves. This companionship will turn into enmity on the Day of Judgment, except for the pious. Therefore, a Muslim should distance themselves from bad company and choose righteous companionship, as the Messenger of Allah, peace and blessings be upon him, said: "The example of a good companion and a bad companion is like that of the seller of musk and the blower of the bellows." Accompanying wicked people is not permissible and is one of the causes of a bad ending and falling into their immoral ways. There is no obedience to a creature in disobedience to the Creator. Walking with a companion who displays her adornments is not permissible and brings evil upon you and your family. It is sufficient for you to contact her by phone while continuing to admonish her.