Can I ask my H.O.A. permission for my son to park his work commercial van in front of my condo ?

I don't think they'll give permission.  A van with a tall ladder rack being parked outside every day is exactly what the rules are meant to prevent.

You can always ask, but don't hold your breath for it. HOAs are notoriously run by the most anal people who get an abnormal satisfaction from causing people the greatest amount of grief possible.

Your son will likely have to find available parking out on the street (if there is any) or make some other arrangement with his employer.

You can ask, of course, but I doubt if they'll give dispensation. Sounds like he'll need to park elsewhere or maybe leave it at work and make his own way backwards and forwards.

No, I don't.  If they change the rules for one person, they would have to change it for everybody.  HOAs can be nasty folks to deal with.  Ours has nothing better to do than to cite people for issues that are not even on their property.  Why can't he get the company van at work and use it all day long, park it there and drive home in his non-commercial car?