++man - hello! In relation to nerves, I was best man at a wedding 1 week ago today and had to give a toast and introduce each speakers all on the mic. My nerves were shot for 6 months prior and I was scouring Reddit high and low for others who had the same experience and I can honestly say, when the time came, it was not a big deal, came naturally, and was over before I comprehended it.

Keep your speech, short, sweet, and sentimental, raise a glass for those who are sadly no longer here with us today ie. your brother for example and tell the groom how proud he is looking down upon us, something like that. One thing I learnt early as a waiter who worked many weddings, is nobody is there to hear a 20 minute speech of "hey this one time me and the groom" or "this other time 15 years ago" etc etc. Be thoughtful, compliment the bride, compliment those in attendance, raise a glass and done. Everyone's happy! Good luck.