Ciao @diana titovaite43 and welcome to our community. Your son can't use his recovery certificate as a super green pass, because recovery certificates are only valid for six months since the date of the first positive test result. According to information I received from the Italian health ministry's Covid hotline47 in late December, "fully vaccinated" for super green pass purposes in Italy is two doses.
Is it marked 1/1 because your country only offers one dose of vaccination to minors?