chickenpox (also in toddler)

I think Tyler has got chickenpox. In the last hour he has got little red pimples come up over his body (about 12) he isnt itchy and seems ok in himself although has had a rough week after last Saturdays episode. Whats the best way to go about this as having 4 im willing to bet they are all gonna go down with it. Is it dangerous for Emily (6weeks)

thanks ladies

xx