Yes indeed, the law will weigh up the intention in the killing and the attempted murder. He intended to kill one person, but killed another. The doctrine of transferred malice will apply.
Given that he now has one conviction for murder, one for attempted murder (which carries the same sentence as murder); possession of a firearm and wounding, it is possible that given the totality of the seriousness of his crimes he could get a whole life tariff. Three victims, premeditation, planning, a firearm could lead to that.
It could be that he will get a minimum term of 30 years (or even more) rather than a whole life order. I'm not a criminal lawyer so perhaps someone with more experience than me might be able to say.