Yes parents can attest photocopies of their child's documents unless not explicitly forbidden in the rules (i.e. the rules for submitting application must not mention photocopies should only be attested by notary or government officer of BS17 or higher not related to you). You can even attest them yourself by writing "This is true copy of the original" and signing your statement, something called self attesting , but it is better to go through rules or guidelines first.

__________________
The precondition for existence of a higher humanity is not the state, but the nation possessing the necessary ability.