GPS wouldn't stop obstacles from hurting him. I tell my clients that a GPS is good enough to get you to the building, but you still need to use your skills to find the door. And a GPS can tell you which street to cross, but not *when* to cross.

It sounds like he needs more training with the white cane. And to apply for a guide dog, he would need exceptional orientation skills (as he isn't feeling the ground with the cane anymore).

> So I'm only asking if we can find a real functional device that can help in this tasks

What exactly are his tasks? If it is getting around, then the white cane is the standard. He may not be using it properly, though.

Another option (albeit more expensive) is Aira. (https://aira.io/) You essentially have a personal assistant available over the phone. But it isn't cheap, I should mention.

This is such a good question. It is also an extremely open one.
More - and better - long cane training is necessary. Get on to whatever agencies near you offer this training and push them like mad until he gets the support he needs.
I love my cane. I don't care what others think of me when I'm sweeping my way through places etc. When I use my cane it's an extension of my own body.
I could talk for ages about this kind of thing.
I use a wheelchair as well as my cane due to other disabilities besides my blindness. I've just got into haptic (vibratory) mobility aids. A long cane as well as something like the Sunu Band from www.sunu.io or the iglasses by Ambutech could be a really useful mobility strategy.
Sorry if this is muddled. You should find both these aids by doing a search on them.