Is the amount of money received every three months by a poor young man, after being exposed to a work accident and suffering a permanent disability, halal or haram, and how can he expiate for consuming haram money if that is the case, especially since he traded with it for more than six years?

The cases for your compensation for an accident vary depending on the nature of the party responsible or the insurance provider.

If the company was responsible due to negligence or transgression, then it must pay the arsh (blood money/fixed compensation) as a lump-sum compensation for the damage, and it may be paid in installments. If the company refers you to commercial, governmental, or Islamic insurance, there is no objection for you to accept from it, especially if the compensation is continuous in cooperative insurance.

However, if the company was not responsible, it is not obligated to compensate you. But if it refers you to insurance as a gift, there is no objection to accepting it. If the insurance is governmental or Islamic, there is also no objection.

If you are the one who obtained insurance with a commercial insurance company (directly or through deductions from your salary), then you should only take what you paid in premiums, and give any surplus in charity if it is not possible to return it. The ruling differs if the insurance is Islamic or governmental; in these cases, you may take the full amount.

As for the funds you received and invested, if they were permissible, there is no problem. If they were impermissible, you must return them to their owners or give them in charity. Regarding the profits derived from them, the preponderant opinion is that they are yours, as there is a difference of opinion regarding whether profit follows the money or the effort, and the closer opinion is that it follows the effort.