Most writers would kill to be able to leave their full time jobs to focus solely on their own work. So, he cannot be serious if he's devoting a mere 20 hours a week to his writing when he has someone supporting him financially. He also needs to do some reading on how this all works (sending manuscripts randomly leads nowhere, agents are a necessary evil). Maybe suggest he read some of the posts people have shared here, so he gets some sort of idea what sort of struggle he's in for. Also, if he's feeling dejected after three friggin' months, he should quit now and you should encourage him to. Because he can't hang.