I can reassure you:

a) I don't work at a burger restaurant

b) I don't have a friend who lives under a rock

c) I don't go out butterfly-catching

d) I've never dug up a grave to retrieve a magic hat

e) I do, however, have a neighbour who plays the clarinet...

I watched Spongebob all the time when I was a kid and it never did me any harm. I think it's a whimsical show with a lot of very clever humour and well developed characters! I certainly don't see how you could describe Spongebob as  "mean or selfish" - if anything, he's overly naive and nice rather than mean or selfish. 

As for laughing at others, well the show is a comedy and a lot of it is slapstick. Of course characters are going to laugh at each other - a little bit of humour is fun for kids! Sure, it's not getting your kids to read Proust aged 4, but I don't get all the hatred for the show. In terms of the IQ evidence, it's a clearly acknowledged fact that IQ is about as good a measure of 'intelligence' as whether someone wears glasses or has blonde hair.

Yes, I used to like Spongebob some years ago because it made me laugh, but now I really don't like him anymore. He's a mean, selfish creature, rejoicing in the misfortune of others and even if it's "only" a cartoon, it makes me angry to watch it and I think he's a bad example for children. So I wouldn't let me kids watch that.

I just looked it up here is where it comes from.

Unfortunately I can't paste into italki on my phone, but you cam easily find this information on Google.

A study was done to see how the ability of a child to concentrate after watching TV is related to the rate of change of scenes of the TV show.  A group of four year old children split into three groups. One watched a show in which the scenes changed slowly and another where they watched a show where they changed relatively quickly (Spongebob). The third group watched coloured pictures.

After nine minutes of  watching, the children's memories and ability to follow rules and resist satisfaction were tested. The children who watched Spongebob performed the worse.

The conclusion: fast paced TV shows affect children's ability to concentrate immedietly after watching (which is nothing really groundbreaking).

It has nothing to do with bad morals or picking up bad habits. It has to with children's ability to concentrate after watching fast paced shows. Spongebob was just the show they used to test this with. This is just my speculation,  but I suspect the same would apply to any fast paced activity, like sport.

I also suspect that the pace of Spongebob isn't significantly different to just about any kids show. I'd be interested to see if there's a list of TV shows with their associated average time per scene to check.

As long as children do their homework before watching TV or a while after, there shouldn't be a problem.

I thnk your brother is right.  Kids will emulate the values taught on tv programs.  Sit down and watch a few episodes yourself and have a good hard look at what they're really teaching kids on that show.