Jamie - 1
Spending a bit of time in the sauna had sounded like a brilliant idea when Jamie had gone in. Lounge around in the steam for a bit, until it was too hot and he had to go cannonball into the pool like an idiot. But, the sound of screaming brought him dashing out in time to see Scorpius fall into the pool while on fire and a small flock of birds diving at the party-goers.
Then it was all chaos.
Birds and people equally dangerous to themselves and each other swarming all over, flames, hexes, screams. It was like nothing Jamie had ever seen outside his uncle's memories and memories did nothing to prepare the reality of the smell of burning flesh.
His first thought was to find Al and Lilu. Silently thanking his dad for being so damn paranoid when Jamie was growing up, he dodged birds and people, shattering glass and stone, flying hexes and attempted hexes. Seeing three of four of the birds descend on someone -- he couldn't tell who because he had to duck to avoid a talon through the eye -- he sent his Patronus racing toward them. It wouldn't do any damage to the birds and it shouldn't take any damage either. But, it should distract them enough for whoever it was to get to safety.
Probably couldn't use that trick more than once, but once was enough when he had to find his siblings. "Lilu!" he called out. "Al!" Dodging debris, he'd search until he found them and got them out of there.