I'm worried that my father is smoking and vaping too much

My sister moved in with my dad during lockdown. She has messaged me to say she is concerned about the amount he is vaping and smoking. Apparently, he is vaping the equivalent of 30 cigarettes a day and has started having a few rollups, too.

Despite being a smoker most of his life, he managed to quit a few years ago but seems to have taken it up again. When my sister told him she thought he was vaping too much, he reacted angrily. What should we do?

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