It is difficult trying to explain to children. Has she watched the Lion KIng?
If you want (and she wants) and you think it will help, I'd be happy to put Thomas on the Bridge Kids (Tribute pages) on the website. That way she'll have somewhere to go to see him when she wants. You can email me a picture: Burpdog@msn.com It might help her if she writes me a letter about Thomas when you send the picture
edited to add: Please give her my sympathy of Thomas' passing. Tell her I know how hard it is