SIL buying my son clothes?!

Aileen • Mommy of 2. 2 previous MC.
Alright so my sis in law and I have had a rocky relationship but we still let our kids play and sleep at each other houses. Her son is 8 and mine is 3, turning 4 in September. The issue is that I just found out she bought all kinds of clothes for my son to when he sleeps over their house. I found this kind of weird and sort of disrespected for the fact that her son told me about it and she never said anything. Am I over reacting? We are spiritual and there are certain types of logos that we don't let him wear. Idk if it because she has been Ttc for 6 years... What do you ladies think?