Helping out towards bills etc could be classed as gifting the money. So long as it’s less than £3k per year, it’s not considered for inheritance tax purposes.
A wealthy person could quite easily swerve the inheritance tax thing by paying mortgages and leasing cars for people. Tax man ain’t stupid so they look at the value of ‘gifts’ like that.
I’m fairly sure 7 year thing is proportionate to the amount of time which has passed since the gift was given.
Ie, if the worst were to happen the day after the gift was given, the whole amount could be included in the value of the estate an inheritance tax could be due. If he were to die 6.5 years after giving the money, the tax liability would have reduced to basically nothing.
I’m not an expert. But I’m sure that somewhere.