Go for it! You've got both of you wanting one another as a positive. It would be harder on him (and you I think) if he had to go into foster care at this time. You can start with him in your household, see how it goes, get extra money for him and support for him, etc. in his father's name and just see how it all goes. Later when he understands more and/or isn't so fond of you or you are having a hard time with him, then adjustments can be made?