What is the ruling on the pension that a friend of mine, who suffers from chronic asthma, will receive, as he wants to retire and transfer his case to the Social Security Fund, knowing that the source of the Fund's money is a percentage deducted from citizens and invested in hotels and building homes?

If the pension your friend will receive was originally deducted from his salary, then there is no Islamic impediment to him taking it. If the funds deducted from employees are invested in permissible (halal) ventures, then he may take any profits that exceed the amount originally deducted from him. However, if they are invested in prohibited ventures, then it is not permissible to take any amount exceeding what was originally deducted from him, unless it is with the intention of disposing of it and spending it on charitable causes, on the poor, and on the needy.