I'm beside myself with worry over this, but I am also Australian and have a slightly different level of water safety expectations so please UK be kind to me when I ask this; I also lost a sibling to drowning when younger.
These people have four children under 10, with the youngest being 2 - including two very boisterous boys (not the youngest). They have brought a stand alone pool and had it put around the side of the house; there are NO WINDOWS OR DOORS looking onto the pool.
Neither parent is going to win parent of the year but dad is an absolute deadbeat and heavily into drugs. Mum is often not at home, leaving dad with the kids, and the damn pool. Dad often leaves them to go and meet his scummy friends and will leave them for max 15 minutes at a time. If he is home he is rarely outside with them in the garden.
I will never find this acceptable, it just is not going to sit with me ever, however, the AIBU bit is should I be raising this with them, with someone else, with a safeguarding organisation? I do get that water safety education in the UK is not as great as it should be and it hasn't been hammered in to people here like it is back home which is why I am wondering about having a chat with them, but what happens then if the situation doesn't improve and I decide to let an organisation know?