Please help me !!!!

My son doesn’t have an appointment til Friday. But I can’t help to think what’s going on with what’s wrong? I started noticing he would have bold spots on his head. I didn’t think much of it at first but after would notice it more. Nothing has changed he goes to the same person who cuts his hair he still uses the same shampoo no changes at all. The more I noticed his heart fall off my mind went somewhere else (cancer) I don’t wanna think about it I don’t wanna think it’s that I’m not so well informed but idk what else to think I’m scared I’m overthinking can someone please tell me what makes hair fall out why does he have certain bold spots he has never had this before ever his only 3 idk what to think 💔😞