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
Also there is another private school in the area, Blue Lagoon is near Villamartin, this is a new school, check out
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)
I hope this info helps you.