You can give what you like.
You have a personal tax free limit each year of £3,000 to give. This doesn't form part of your estate.
Anything else you give forms part of your estate.
Your personal inheritance tax threshold is £320,000 each. So you can give up to this amount and is not taxed after death for inheritance tax.
After 7 years this amount resets so you can then give another £320,000.
If the amount you gift goes over £320,000 any amount over this in those 6 years incurs 40% inheritance tax (front loaded sliding scale).
My advice to you is get your husband to transfer the £15,000 pension into a joint account in both your names.
Then, from here, you can give the first £6,000 this side of April 5th (tax year) and another £6,000 after April 6th. This uses both you and your husbands £3,000 giving allowance for both tax years.
If, if one of your children is under 18 and has a child's isa you can transfer £9,000 inheritance tax free into their account each year.
Ultimately anything over these smaller tax free amounts will become an amount against your £320,000 inheritance tax threshold. In the event of both of your deaths and you've gone over £640,000 (joint) your estate would pay any tax due. You can also both gift £175,000 each to children from a main residence as an asset.
So the inheritance pot is generous but has to be given in a way to maximise both your allowances.
The clock starts ticking the moment it's transferred and in 7 years it doesn't count anyway.
So the answer is yes. if you give from a joint account, and both you and your husband are in good health you should be more than ok.