Baby Blue Tits

Hey there guys,

i have been very fortunate to have had a blue tit nest in my shed, she started with 3 babies, but one died after two or three days, he looked way less developed and smaller than the rest :/

anyway, its been about a week now and the two left both seem very different, one is standing and attentive and looking round and the other struggles to stand has less feather and looks way weaker, now i dunno if nature is like well survial of the fittest here, but id hate to see one die and i didnt know of there was anything i could to to help the little guy out.