A true friend does support when one needs him/her the most. However, life is too fast and each individual is engrossed in different issues in his/her life.
Job-routine doesn't let one think about anything else. After the shift, an individual is utterly knackered. All he/she needs is a sound sleep or a companion with whom he/she may share feelings and feel lighter. Thus, a friend not being with one who needs him during the bereavement period is not a big deal now-a-days. It's understandable.
It's wise on one's part not to hold grudges against the one who wasn't there during the bereavement because he/she has other things to take care of.
In case, some manage to spare time for the friend in need. It's respectable but the same can not be expected from all...Opinions may vary and I respect opinion of others!...😊👍