I share your concerns, as I am several years older than your father. But I have not gone quite to the extremes you have, though I have thought about it.
In another life, I used to open my mail on my kitchen table as I was eating breakfast, reading my Wall Street Journal. I omitted that briefly when anthrax spores were being mailed around after 9/11.
Today, I do wear gloves retrieving the mail - they're cheap and easy - I open my mail in a hallway away from the kitchen using a metal letter opener rather than opening them with a finger which I like to feel is less likely to disperse dust/stuff from any envelope, or puncture a finger on a staple inside the envelope. If I had an attached garage as you do, I would use that, but I don't.
I dispose of junk mail unopened, and remove the outer pages of any magazines or other printed materials, and put the naked magazines in a pile to soak in the sunshine later for a few days.
Packages I try to minimize receiving, but still Amazon calls at times.
I have reported ordering EarPod Pros back in early January when they were listed as in stock ( hence probably in the USA ) Alas, after I submitted my order, I was told they would arrive in early March, which I assumed meant they had not yet departed China or might be enroute.
When they arrived I donned gloves to open the package, and then wiped all plastic surfaces of the case ( inside and out), USB wires, and EarPods themselves with rubbing alcohol and set then aside for a week. I have been using them now for at least two weeks and I have remained healthy.
Like you @Vilen I suspect much of this is overkill, and have been assured it is not necessary. But while the risks, seem low, the stakes are potentially at least pretty darned high.
After opening my mail I remove my gloves and wash my hands carefully with Dawn for 25 seconds. My hands are getting fairly dry so once my hands are no longer moist at all, I apply some hand lotion of some type too.