No, Avios and Tier Points are always allocated to the individual. You will only receive the 11k allocated to you, and your son will get the same.
What a household account does is
pool the Avios available amongst individuals. This means that although your son will have 11k Avios from the flight, you will have access to them and can spend them as they are pooled with any other household account members. Of course, this is true for all in the account, i.e. your son will now have access to
your Avios, so you'll need to trust him not to spend yours
Household accounts are a good way of accessing relatively small amounts of Avios from people who otherwise don't accrue enough to be useful. There are some limitations with them, primarily you are much more limited on who you can spend Avios on - basically those in the Household plus a list of 5 others nominated individuals, but it sounds like it could be an appropriate approach for you.