That's always a possibility but I've seen my Grandpa die of a broken heart after my Grandma died. The night of her funeral he asked his children if they thought someone could die of a broken heart and after that it took him less than a year to go himself. I'd never considered that saying to be true until then but I watched it happen.
"It usually appears after a significant stressor, either physical or emotional; when caused by the latter, the condition is sometimes called broken heart syndrome"
Don't know the details, didn't read the comic, and don't really have a personal interest on the history so what follows is just general speculation. She looked depressed enough to commit suicide. Is a fact also that people that orbit around drugs, tend to die younger, by suicide or by the effects of the drugs.
In any case if two relatively young people die in a short interval of time would be wise to look for environmental effects. Oil pigments have chemicals, and some colors were removed for being notoriously unsafe. Going further, slow poisoning to eliminate opponents with the benefits of plausible deniability is trendy among some criminals unfortunately. If somebody "dies of grief", research for discarding a hidden toxic should be started, just to be safe.