That's a liquidity crisis, not insolvency. They were invested in long term maturity US treasuries! The safest asset there is (arguably)
Ish. On a mark-to-market basis they had insufficient reserves. That's closer to insolvency than illiquidity. The mismanaged duration is closer to illiquidity. But not of the sort a lender of last resort could save them from.
Same with their mortgage-backed securities.