Many able-bodied people often find it difficult to interact normally with individuals who have mental or physical disabilities. Both in their professional and their private lives. The principle is, however, actually pretty simple and universal. Treat everyone the same! If you see a person who clearly needs helps, then speak to them. Whether they need assistance because they are in a wheelchair and cannot overcome an obstacle or because they are lost is irrelevant.
People who view individuals with disabilities as “in need of help” purely because of their handicap, treating them with over-exaggerated concern, care and attention, are discriminating against them just as much as those who believe that such individuals lack certain abilities and talents because, for example, they are in a wheelchair.
So look at the person. The man, the woman, the customer, the employee – not the person with the disability. Offer help if it is clearly needed but never give it unasked. There is no clearer way of telling someone that you have no confidence in them!