First off I'm impressed he's learned 12x before 3 & 6 tables.
Sounds like he's got ability but needs practice and to build up speed.
my suggestions for free multiplication games would be:
Maths Champ:
games ages 7 to 9 here: www.mathschamps.co.uk/games7-9
this will give 3-9 times tables practice, which basically means he's only missing 11s.
which he can get practice from from the 9 to 11 bit of maths champs here: www.mathschamps.co.uk/games9-11?
-------
Table Trees: www.amblesideprimary.com/ambleweb/mentalmaths/tabletrees.html
this is from Ambleside primary school (which someone else linked to above) - very gentle practice specific to individual tables - good for starting to learn.
------
Timez Attack:
www.bigbrainz.com/
there is a free two platform version or you can pay for different versions with more platforms - we found the free version was enough
When you start it will test your DC to work out where they're at and go from there.
Warning this can be pretty stressful - you're a little ogre racing through a dungeon or a castle. You will come across multiplication problems - the game will show you the problem vertically with domino type blocks alongside showing multiple additions: so 4 x 5 will appear as 4 dominoes with 5 blue dots. These dominoes jump off the wall and turn into snails which you catch. You then throw your caught snails at the wall - as you do the computer counts up by whatever you're multiplying - so in this case 5 - 10 - 15 - 20). You then type in the answer on the old fashioned vertical multiplication problem. At which point a medium-sized ogre comes out and quizzes you on this problem and two others. (that's the stressful bit - because he will crush you if you get it wrong too often). Every so often the Big Ogre comes along and quizzes you on everything you've done so far - he's scarier. The programme gives you the ones you aren't good at again and let's you know what you are getting consistently right.
DDs loved it - but youngest (age 8) finds it pretty stressful. There is an inverse multiplication facts (simple division) version to go onto once you've mastered this.
------
Mumsnet has a grid multiplication game which is good once you've mastered all tables but need practice with things mixed up a bit: www.mumsnet.com/learning/maths/interactive-times-tables-activity
-------
Wodland Junior School's mathszone has a ton of links to games to support any area of maths - just click multiplication and go from there: resources.woodlands-junior.kent.sch.uk/maths/
---------
Finally you can play multiplication snap.
Take Ace (=1), 2 -9, Jack (=10), Queen (=11) and King (=12) or chose a number of the day - say 4.
Shuffle deck (agreeing cards as above). Place face down.
Flip card over - first person to give correct answer keeps to cards. Carry on until you're through the deck (use half deck) if just starting out. Try and lose a bit to give them confidence.
person with most cards wins!
Well that should be a start...
HTH