I presume she also has a microwave, hairdryer and washing machine in addition to a mobile phone. All produce small levels of RF Radiation - but at a high rate than smart meters.
If she is on public transport or in a busy office she will be in close proximity to dozen of people with mobile phones constantly emitting rf radiation at several times the level of smart meters.
The problem is flat earth / covid denier types coupled with daily mail type sensationalism that you see far too often. Usually a non-peer reviewed piece of "research" by dubious "experts" add in the word CANCER to get headlines and notice.
Example was the headline a few years ago that "eating minced beef can cause elevated chance of cancer". This is actually true - HOWEVER, when peer reviewed they said you would need to be eating 1kg (7 quarter pounders) of minced beef every day for over 20 years for it to have a noticeable increased chance of cancer - an elevated risk of cancer will be the very least of your health issues if you consumed that many burgers. But the daily mail and flat earth types "forgot" to mention that part