Tiels are such incredible birds and I am so excited for you to get your baby and so happy your grandma took in Yoshi!
Yoshi must have been so heartbroken and he can now have love and a happy home again. That makes my heart melt. Cockatiels are the best and a tossed aside birdie is so sad. Pictures pictures pictures!
Please do what you can to get a wider cage. Even the finch cage from petco for about 40 dollars would work for a while. It is 30" wide and 18" deep. It can also be purchased online. Then save for a flight if you really can't get one right now. They do have flights on Amazon for 99 dollars and free shipping though.
Also check out the dyi thread for toys. Lots of thos can be made Inexpensively, especially shreadable toys.
Think coffee filters, non metallic ,moon coated cupcake liners, tissue paper, finger traps, coin rolls, playing cards, balsa wood, sea grass from the rodent section of the pet store, etc