There is nothing more cowardly than suicide. It takes a brave person to face their problems and deal with them.
Suicide is Biblically wrong. It’s playing god. He wasn’t afraid of living through the pain of terminal illness, nor was he distraught over the loss of a loved one and couldn’t deal with the pain. He lost it, and took it out on what he perceived to be his tormentor(s).
He played god in more ways than just taking his own life. Lashing out like that is many things, as I’ve mentioned, it’s crazy and murderous. But cowardly it was not. That was not some quiet, personal hell leading to death at his own hands. He no doubt thought he would be regarded as something of a martyr.
He now has an eternity to rue his actions.