Could I remove an outdoor cat's collar when it is not mine

I do not know who owns the cat, he just sort of showed up one day, he was limping badly and is very thin. We've been feeding and giving him water since he's been in kind of rough shape, but thankfully his limp has gotten better, but he's still concerning thin. He has a "collar" but it isn't a proper breakaway cat collar, it looks like it is just a grey zip tie, it doesn't even look like it could be removed normally it would have to be cut off him. I kind of hate this cat's "owners" I'm scared that the collar could get caught on something or get pulled tighter and start suffocating him. He's such a sweetie. I'm not planning on taking him as I live with family who is allergic to cats. I'm just really concerned for him. Location: Virginia