He may have had profits allocated to him in the last financial year, it's normally under the tax free threshold so no tax return is needed but the family trust reports who it has disbursed to so its on record with the ato. It could effect you if your dh was to run his own business and needed to do a similar thing, you need to know how much he has been allocated. If your ds has a bank account in his name any interest her earns needs to be considered too as that is considered to be income too and could change the amount that can be allocated to stay under the tax free threshold.

There should be any long term issues as long as you know what is happening and if you were ever to have a family trust they would have to stop disbursing profits to him.

We would have had a similar issue with our trust and my mil's if she hadn't passed away.