Is a one-third share of the ill-gotten money invested by the son considered permissible or impermissible for the investor?

Whoever knows that the money itself is forbidden is not allowed to invest it or partner with its owner in trade. If the owner of the money is exposed to danger upon its return, then he should exert his utmost effort to return it in a way that does not expose himself to harm, as Allah Almighty says: "So fear Allah as much as you are able" (At-Taghabun: 16). If he is unable, he should keep the money until it is possible to return it. If he then despairs of being able to return it, he should give it away in charity. It is not permissible to invest it or dispose of it because he does not own it.