In the Name of Allah, the All-Merciful, the Mercy-Giving.

 

All praise is due to Allah. Peace and blessings be upon Prophet Muhammad.

 

As long as your husband’s sisters use these makeups in a permissible way and do not wear them in front of other marriageable men, he may buy these items for them. I cannot see anything wrong in doing so.

 

In normal cases, a male mahram does not look at his female mahram with desire. Therefore, a Muslim woman is not obligated to wear full hijab in front of her male mahram and she may reveal of her body such parts that usually appear in her housework, such as her head, forearms, shin, and neck.

 

Ornaments worn on these parts, including makeups, may be revealed as well.

 

But in abnormal cases, when a woman knows that her male mahram may describe her to others or that his looks to her are unusual, she has to take on her full hijab and be more reserved with him.

 

With regard to the costs of these makeups, it is your husband’s responsibility to spend on your family. If he fulfills his duties in this regard, you should not interfere in his relation with his sisters. Such interference will likely cause troubles with your husband and may be interpreted in a wrong way.

 

Almighty Allah knows best.