Our DGS could say his times tables with no problem, but he also enjoys being asked random questions from them. He is probably not typical, so I can't really help. I remember being asked random sums at the table when I was little ( also collective nouns, spellings, etc). Our family all love games and quizzes.
If your DGS does not have that sort of mentality, you could include little sums in every day conversation, asking him to work out, e.g. "I'm going to need 4 eggs a day for breakfast every day next week - how many eggs is that?", or "This costs 12p - if I buy three, how much will that be?". It may help if he sees that it is not just abstract numbers, but something relating to real life. Especially with relation to pocket money. Working out sums with money is a good exercise- I remember being good at sums (all that training over the bangers and mash) but my mind went blank if a currency was involved. I noticed this in my oldest when he was at primary school- he is now an engineer and a maths whizz, though.
(As Bluebelle has said, these days they just seem to recite a string of numbers. My DGS does this, too, at his German primary school. If they just say 14,21,28,35,42 how are they going to know that 6 X 7 is 42? All that tells them is that 42 is divisible by 7)