If this is for a fence slat use a # 8 galvinized, if it's for a 2x4 railing use a 16 D galvinized. If you want a better hold use a star head deck screw these are easier to screw in than a phillps head and can be removed easier too.
Use spiral galvanised nails.
If the bent nail is used to fix a plain wire or strand of barbed wire to a fence post, and the bent nail is pointed on both ends, then it is a staple.
the door panel has a few clips on it that just snap in
glue it with good glue from Menards
nail file
buy new ones
If its simply an eyesore and not a health or safety issue, there is little you can do about it but ask him to fix or replace it.
I recommend adding acetone (nail polish remover), but it may be hopeless.
You just need two pronouns to fix this sentence.The correction is:"Will you help those people paint their fence?" asked his father.
nail polish will fill it in.
If loose they will need replaced.
The best thing to do is to purchase or make a new barbed wire fence. It can be painful to try and fix one as the barbed wire easily cuts a person.
Because they do not have an edge or point that is sharp, they are less accurate and less refined. If you must fix a blunt nail, drill a much smaller hole first