Is it ever possible to tell the purpose-driven purpose (in general sense) of a respected distressed disabled person? I believe when a person is born God chooses him or her to carry out an action on this planet. And until that action is carried out they can never retreat from this world.

Paralyzed people fully from head to toe who are like so from birth and those people in life who developed some intense illnesses that they never quite got over with and can't rebuild their lives or help their family, what was that purpose-driven life for them?

I am asking this because I volunteer at an organization where broken people and people in wheelchairs come for help. I talk to them. I hear their distressing everyday life story. I want to know what was that God's chosen action that they have to carry out on this planet when they are so vulnerable themselves and are suffering so much? 

I also heard on tv that a pastor saying every person's life has a grand design. So this question.
[Isaiah 43:5-7] Fear not; for I am with thee: I will bring thy seed from the east, and gather thee from the west; I will say to the north, Give up; and to the south, Keep not back; bring my sons from far, and my daughters from the end of the earth; every one that is called by my name, and whom I have created for my glory; I have formed him; yea, I have made him.

The purpose of life is to live for the glory of God. So all things and people, that include man and women, healthy and sick, young and old are created to glorify God, there is no other purpose.

[1 Corinthians 10:31] Whether therefore ye eat, or drink, or whatsoever ye do, do all to the glory of God.
[1 Corinthians 6:20] For ye are bought with a price: therefore glorify God in your body, and in your spirit, which are God's.

Now we can ask, How we can glorify God?

[Romans 3:10-18] as it is written, There is none righteous, no, not one; There is none that understandeth, There is none that seeketh after God; They have all turned aside, they are together become unprofitable; There is none that doeth good, no, not so much as one: Their throat is an open sepulchre; With their tongues they have used deceit: The poison of asps is under their lips: Whose mouth is full of cursing and bitterness: Their feet are swift to shed blood;Destruction and misery are in their ways;And the way of peace have they not known:There is no fear of God before their eyes.

We can't
The only way we can glorify God is through Jesus Christ

[John 14:6] Jesus saith unto him, I am the way, and the truth, and the life: no one cometh unto the Father, but by me.

Now that we are in Christ, this is how

[1 Peter 1:16] because it is written, Ye shall be holy; for I am holy.

Being Holy, that is

[1 Thessalonians 5:14-22] And we exhort you, brethren, admonish the disorderly, encourage the fainthearted, support the weak, be longsuffering toward all. See that none render unto any one evil for evil; but alway follow after that which is good, one toward another, and toward all. Rejoice alway; pray without ceasing; in everything give thanks: for this is the will of God in Christ Jesus to you-ward. Quench not the Spirit; despise not prophesyings; prove all things; hold fast that which is good; abstain from every form of evil.