Ella
Welcome to EOS. You will find very helpful and truthful advice on here.
Villamartin is a nice area, they have an International school near there in San Miguel, its called Mar Azul International school, it's a private school but probably a better option for your 13 year old. Spanish schools are fine but definitely for kids who are younger than 10. Check out
www.marazulschool.com/en/index.php
Also there is another private school in the area, Blue Lagoon is near Villamartin, this is a new school, check out
http://www.ellimonarinternational.com/villamartin/index.php
I agree with EOS team, that your 13 year old will find it difficult at that age.
There is also a dance school in Villamartin, maybe your Husband could contact them, they may need a musician. Also your kids might be interested in dancing.
Ghost Performing Arts Academy
67 Calle rigoletto , 03189 Villamartin (Alicante)
Tel: 679531737
I hope this info helps you.
Regards