Merry Christmas and Happy Holidays to everyone here! I hope you've been getting in some quality family time or will soon.
To be honest, I get a very strong "not my problem" vibe from SA towards Chloe. That isn't to say that he didn't love her and enjoy her company, but more like someone else would worry about her and he'd just get to have fun when she was around.
As an example, my one cousin was getting married and had made her older married sister her matron of honor and her little 2-year-old niece her flower girl. Because grandma had always been such a big help with the little one, mom pretty much took the baby to everything (bridal showers, dress fittings, the wedding, and reception) and just assumed that grandma was keeping an eye on baby. And because grandma wasn't specifically asked to look after and was dealing with arrangements and the financial sides of things she wasn't watching. At the shower, the toddler pulled a display table down on herself that had lit candles on it. Got hot wax on her dress and broke the glass votives but luckily wasn't burned or cut, just scared. At the reception, she wandered out into the parking lot TWICE, again lucky that someone saw her and grabbed her before she could get hit by a car or wander away completely. Mom was adamant she'd done nothing wrong but after that Gma ALWAYS asked "who's looking after her?" at family get-togethers and events.
That's exactly the vibe I get off SA. We don't know for sure that he was ever left alone with her prior to this. We have photos of him with her, but they all seem to be some kind of event and with other people about. And even then there are times Chloe is just kinda 'there' by him but not his focus at all.
He sure seems far more interested in this dog right now then Chloe. She's not even in his line of sight. She could easily bolt and get herself into an unsafe situation if he was the only one there minding her.
This is a very sweet photo, but it's clear grandma is the one doing most of the actual minding and helping, holding the bag for the eggs and encouraging her while he snaps pictures. And there is NOTHING WRONG WITH THAT. There are some grandparents who are just not that hands-on, don't do diapers, physically can't keep up, etc. It doesn't mean they don't care just that they don't get left alone with little ones because they don't/can't stay focused on her and her saftey. He looks like he's having fun following along, but could just as easily decide he's bored and wants to focus on someone/thing else and let grandma and her keep going without him.
Chloe and mom had been playing in the splash pad before he came up. Why did she stop playing in the water after mom left? Those things can keep little ones entertained for hours till you finally have to step in and pull them out kicking and screaming to dry off, warm-up, and get something to eat/drink. I don't know if he was wearing swim trunks under his shirt but part of me wonders if mom made her come out while she was only with SA, not trusting him with her in the water where she could slip or get into one of the wading pools with him not paying full attention and so he encouraged her to wander away to find something else to occupy her because 'mom said no more splashing till she got back'. She goes over to the windows and he decides to try something he thinks is funny out not thinking about if she's still wet and slippery, or how squirmy she might get because he's never had to think about that before. Someone else was always there to do that for him. And next thing you know she's disappeared from his hands before he can do anything to stop it.