Priestly Blessing - Birkat Kohanim

Hi Rabbi, There is a special hand greeting done in the Star Trek series by Mr. Spock to "live long and prosper". I was told it’s a Hebrew blessing and I have also seen it on plaques and on souvenirs. Would you please help me learn more about it? Thanks.

We are Kohanim. My elderly father can't get up to do Birkat Kohanim, or even go out to the Shul for that matter. What should he do? Thanks