Suicide is an illness, not a sin. Nobody just calmly decides to end their life by suicide and burden his or her loved ones with that death any more than anyone calmly decides to die of cancer and cause pain. The victim of suicide (in all but rare cases) is a trapped person, caught up in a fiery, private chaos that has its roots both in his or her emotions and in his or her bio-chemistry. Suicide is a desperate attempt to end unendurable pain, akin to one throwing oneself through a window because one’s clothing is on fire.
Many people feel awkward and nervous when first spending time with a suicide bereaved person. It will take some time to learn how to respond. It is okay to feel awkward but you don't need to let it prevent you showing support.