It might be possible by placing a buff similar to this:
{
"id" : "disable_heal",
"stat_type" : "disable_combat_skill_attribute",
"stat_sub_type" : "heal",
"amount" : 1.0,
"remove_if_not_active" : false,
"rule_type" : "always",
"is_false_rule" : false,
"rule_data" : {
"float" : 0,
"string" : ""
}
}
this one will disable all healing skills.
You can change "rule_type" : "always"
to "rule_type" : "skill"
and "string" : ""
to "string" : "skill_name"
And maybe try changing "stat_sub_type" : "heal"
to something else