I'm thinking of finding a replacement for me and I don't want it to be my friend.
Why wouldn't you want to pick your friend?
I know that my friend won't be a good replacement for me.
I can understand your predicament in this case. You should help friends when they need it. Not everyone is going to be as good as you once were, but maybe you can train him to be up to standards.
I'm probabaly just going to pick someone else.
I think your friend will be hurt by not being picked. You can get them ready to do the job, you just need to show confidence in them and train them to do well.