Hi Fei Ku,
If I was you, I would call the church and have the church members drive to the spot where the homeless person is and the church can give food, a basic kit ( toothbrush , toothpaste , deodorant , small soap etc ) as well as a small Holy Bible and a tract. The church can take the homeless person to a homeless shelter.
You also can call the police and they will check the homeless person first and if there are no warrants out for his arrest then they will bring the homeless person to the shelter.
I would not approach a homeless person or give money because of one reason. Many homeless individuals just got out of prison or are running from the law.
I learned this from many police officers to keep safe and away from homeless people and if you want to do that then call the church and you can give a bag of food etc. then they will take the bag to the homeless person for you.
This way you are able to keep safe and the homeless person will not know you gave the bag of food or a basic kit to the homeless person.