Wwyd in this situation and how do I fix it if I can fix it.

My 15 month old I the most beautiful corkscrew curls. I wouldn’t need to do much to his hair other than wash it moisturize it and it will be. It was also very think long and soft. everyone was in love with his hair. I never got side eyed when I didn’t braid his hair or anything whenever I just let his natural curls be people would literally ask me what I did to get his curls act and I would say nothing because I didn’t need to do anything .He went to visit his grandma and she put something in his hair. I don’t know what it is cause she don’t wanna tell me, but his curls are now gone and his hair is not as soft as it used to be I can’t just leave his hair out like I normally do because his hair is now fuzzy, and doesn’t retain his curl patterns, even after washing it so whenever I just wash his hair and moisturize it, it just was up and look like I’m not taking proper care of my son’s hair and I don’t know what to do. I get so mad. Every time I look at his hair I’ve been told that I’m overreacting.

So is there any suggestion that you Mommy might have to help me get my son’s beautiful curls back? He had a mix of 3C and 4a type curls