Kay

Mark,
Paul wrote in vs5 “Now she who is a widow indeed and who has been left alone, has fixed her hope on God and continues in entreaties and prayers night and day.”

Paul also says “But she who gives herself to wanton pleasure is dead even while she lives.” vs.6

I ask you, what kind of person is “dead even while she lives?” A person who is dead while physically alive is not a Christian. I see Paul here clearly contrasting the two for Timothy.

Because of that, it’s reasonable that those “dead” widows are the ones referred to in vs.15:
“for some have already turned aside to follow Satan.”