The hospital might not take it directly, but he’d still retain control of it and be able to find a way to exchange it for something the hospital does take.
In a country with a sound financial system, 6 months of expenses in a savings account might suffice. However in a country without a sound financial system you'd want 6 months of expenses in a savings account to protect against your own job loss, and maybe 6 months of expenses in bitcoin/offshore account to protect against a local financial system collapse.
Hoarding USD could also work, but it may be harder to get and it's definitely harder to protect/move in large amounts.
Clearly holding Lebanese currency in a bank may not be useful for holding emergency funds. But I do not believe that it's been shown that at point in time an asset which can drop 50% in value over two months, which is the type of acute timeline in which an emergency can occur, and requires transacting into LBP anyways in this scenario, is useful for holding emergency funds either.