Confused about Aakash

In today's epi we see that Dhariya's mom and Atharva's mom were pregnant at the same time. Devika says "aap papa bane wale ho" but isn't Aakash the elder son? Why does Dhariya only hate Atharva and not Aakash? Only part I'm confused about!

Also, side note - I actually liked and appreciated the whole "periods" episode because its not something we see on ITV and finally its being talked about without being taboo.