Some clarification of At-Tawassul.
For example, if a person has a headache he can make Du^aa’ by saying: “O, God cure my headache”, or he can say: ”O, God cure my headache by the Prophet peace be upon him”.
In both cases the person is asking God, but in one he made tawassul and in the other he did not. There is no problem in both.
It is permissible for the person to make du^aa’ when he is sick and it is permissible for him to not make du^aa’ and be patient with his sickness.
And no Muslim believes anyone creates anything, except God.
The meaning of creating is bringing from non-existence into existence. And no one creates with this meaning, except God. God does not resemble anyone or anything.
If a person has a headache he can make du^aa’ and take medication for the headache, or he can just make du^aa’.
If he takes medication, he is using a means to cure him.
And if he does not take medication and he makes du^aa’, he is asking God to cure him. So there is no problem in both.
And just as it is permissible to make tawassul during the life of the Prophet peace be upon him in this world, it is permissible to make tawassul after his death (as the Prophets are alive in their graves praying as the Prophet said). This is the consensus of Ahlus-s-Sunnah Wal Jama^ah.
So if the person asks God by the Prophet, he is using a means; but this person knows and believes firmly that God is the Creator of the cure, and this person knows and believes firmly that God is the Creator of everything, and that God is the Creator of good and evil. This is the belief of all Muslims.
God ordered the good and forbade the evil. But God is the Creator of everything, and the person just acquires the deed that he (the person) intended to do, and he did it.
For sure God is the Creator of that deed, whether good or evil.
So the choice a person makes in this life will have consequences for the person on the Day of Judgment.