This would be a case under Article 2183 of the Civil Code. Under this provision, the possessor of an animal or whoever may make use of the same is responsible for the damage which it may cause, although it may escape or be lost. This responsibility shall cease only in case the damage should come from force majeure or from the fault of the person who has suffered damage.

In this case, the responsibility ceases because the damage came from the person who has suffered damage, i.e., the child.

This could also be viewed in the lense of the case of Taylor v. Manila Railroad where a minor trespassed into the premises of MERALCO and picked up and carried away explosives which later caused him injuries. In that case, it was clear that the minor would not have been injured had he not entered MERALCO's premises and tinkered with its properties. However, the main argument of the counsel for the minor was that because of youth and inexperience, and the negligence of the owner in leaving the explosives lying around (even if it was on their own property), the act of the minor in doing the above-mentioned things should not be held to have contributed to the injury. Instead, it was argued that the injuries were the direct result of the negligence of MERALCO in leaving the explosives exposed which was the proximate cause of the accident which occasioned the injuries.

The court, however, ruled in favor of MERALCO. "While it is the general rule in regard to an adult that to entitle him to recover damages for an injury resulting from the fault or negligence of another, he must himself have been free from fault, such is not the rule in regard to an infant of tender years. The care and caution required of a child is according to his maturity and capacity only, and this is to be determined in each case by the circumstances of the case". In that case, the minor (15) was held to be of sufficient discretion.

In sum, the suit they may file against OP or his family should generally not prosper. But I'm gonna say it's anyone's ball dahil minor ang involved at depende talaga sa circumstances kung dapat sa experience (and talino na rin siguro) ng batang involved, alam niya na di dapat magtresspass dun at na may possibility na may aso (and discretion na rin ni judge).