Dakota, I agree with FJL as to the order of reactions to losses, and since your co-workers hardly acknowledged the loss of a spouse I wouldn’t expect much from them. They could at least express their condolences & I’m very sorry you have to work with such thoughtless people. I can only hope it is thoughtlessness & not lack of caring.
As for the students, whom are likely younger, they may not understand the loss of a parent and are still at the awkward age to express their sympathy-just my guess not knowing the situations.
As difficult as this time is for you, I think how lucky you have been to have a father you love dearly & to have spent quality time with him over the last months.