What worked for me after after almost 20 years as an on/off smoker....

20 pushups whenever I had a craving. Basically every waking hour (about 18 hours a day back then). This was about 12 years ago.

I estimate I completed about 10k pushups in a 3-4 week period before the cravings gradually subsided.

I had an office job back then and many of those push-ups got done in the men's room.

I did gain weight, some good and some bad, But I was able to trim off the bad weight within a few months.

Good luck, I'm rooting for your and I am sure your loved one are too.