Welcome to Knitting Help!
Yes, the pattern generator is a good idea. You could also take a simple sweater pattern and add in deliberate mistakes: yarn overs, ladders, imperfect darning patches, etc. Would be kind of fun for your mum because any mistake contributes to the overall design (and most knitters have a catalog of mistakes on which to draw).
These are some basic patterns but you can look on Ravelry (free to join) and do an advanced search too.