I'd guess it will be
- possession of indecent images
- making images
- distributing images
The (3) would probably be custodial sentence.
I don't know about Scottish law but in England there is a scale, it used to be the copine scale, which had 10 catagories but in England it was reduced to 5 and then to 3.
IMHO that is a mistake, under the copine scale a picture of a child at the beach could be classed as 1 and a single picture would not attract charging as it may be you were taking a pic of the sea and a paddling child wandered in. It would be difficult to prove you had any sexual interest.
The law has also changed in that a picture of a 17 or 18 year old is classed as a a child. So if you google image Sam Fox you will not find any pictures from when she was 16/17 even though topless pictures of her were in a national newspaper.
Sorry for all this waffle. A first offence and level 1 pics for personal use will probably be a community sentence and it will probably include some form of attending a course to examine behaviour.
If Scotland uses the 1-3 scale then this will be stated in court and probably be reported by local press. And if any images are at level 3 the press will say, "the worst level"
I don't mean to sound as though I am minimising, I learned about the copine scale the hard way when I foolishly allowed someone to borrow my computer at uni.
It also lead to me thinking the law needs to be looked at. 'Image' can be a photograph, but also a drawing or a cartoon.
I have read Game of Thrones, I have seen the TV series. When Daenerys is first married she is 13 in the book. In the TV series she is played by an adult. So you can watch the TV scene and it isn't illegal, you can read the chapter in the book, again not illegal, but if you were to draw or paint the scene from your imagination you would have created an indecent image of a child and this image would be classed as level 3 (formally 5).
A couple of 17 year old 'sexting' can both end up with convictions for possessing, making and distributing indecent images.
And at the same time people with huge collections of child abuse get the same conviction as the 17 year old.
OP
Sorry your brother's behaviour has done this to your family. It can't be easy but I'm sure you are better off knowing about it and they could have not told you.
We always think we could spot someone who is, well insert word of choice, and it comes as a shock when you realise that the nice person you know/knew isn't the person you thought and that you can't spot it.