COVID-19 Pandemic

First of all it doesn't matter if you win this argument. Herd immunity does not require 100% of people to be vaccinated. That's why it's such solid public health policy, and why vaccine mandates are so controversial. It doesn't matter one iota if this one guy and all his friends don't get vaccinated.

Seconly, the first data I found was this.

As of January 8, 2021, 55 deaths were reported, and the mortality rate of COVID-19 vaccination was 8.2 per million population. A total of 37 deaths were reported among long-term care facility residents, and the mortality rate was 53.4 per million population. Top reported comorbidities associated with deaths included hypertension, dementia, chronic obstructive pulmonary disease (COPD), diabetes, and heart failure. In addition, dementia was more likely to be associated with deaths vaccinated at long-term care facilities than at other locations.

Fairly insignificant then. It's less than the chance of being murdered each year (for an englishman). Less than the chance of randomly dying for some other reason that day. And it's less than the chance of dying from running a marathon. Source

I didn't do the sums, but I'd wager it's also less than the chance of contracting and dying from covid.

Unless you are demented or diabetic etc, you're probably fine. Anyway, it's a free choice he can make. None of anyone else's business, unless he's unfortunate enough to live in Italy.