The logical issue your friend is ignoring is that the disease (covid) is proven to be highly dangerous. The vaccine might be slightly dangerous (depending on who you believe). But clearly there are no remotely credible claims of hordes of people dropping dead of mRNA vaccines like there are for covid. So just from a lesser risk stand point, your friend should get the vaccine.
The logical issue your friend is ignoring is that the disease (covid) is proven to be highly dangerous. The vaccine might be slightly dangerous (depending on who you believe). But clearly there are no remotely credible claims of hordes of people dropping dead of mRNA vaccines like there are for covid. So just from a lesser risk stand point, your friend should get the vaccine.