So, for the Orphans Scheme, are children with the same father but different mothers considered siblings?

In Singapore, the Orphans Scheme allows siblings who are all single and whose parents are both deceased to jointly apply for an HDB flat. HDB policy generally refers to "siblings" without explicitly distinguishing between full siblings and half-siblings (i.e., siblings with the same father but different mothers or the same mother but different fathers). In practice, as long as you can legally prove your sibling relationship—regardless of whether you are full or half-siblings—you will be considered siblings for the purpose of the Orphans Scheme. Documentation such as birth certificates showing at least one common parent is typically required.