Point is that your son working on the front line has the benefit of all the PPE etc that the NHS has. OK he may catch it despite all the protective equipment, and be off work for a while, but is unlikely to be seriously ill. However, an 80 year old will not have the level of protection your son has and may not survive.
If we vaccinated the age groups that are currently filling hospital beds professionals like your son would finally find that they have breathing space.