FMV Trust with a life estate

[Marks22]

My mother put her home in a trust, when she passed in 2019 there was a life estate clause in the trust that gave her husband a life esate in the home as long as he lived.  Her husband died in 2024.  Question is the FMV (setup basis) calculated upon my moms death (grantor) in 2019 or at the termination of the life estate ( the passing of her husband) in 2024?

[Hi Palms]

The FMV stepup should be on the termination of the life estate.

It's when the life estate ends and the interest becomes vested in the person(s) (or entity, such as an estate or trust) succeeding to the remainder.