Is there a way to prevent editing of tiles on the start page of windows phone mobile?

[karakawa1]

Hi hope someone could help answer this. I got my 90 year old mother a lumia 640 she loves that I can put contacts as a tile where she can press and dial the kids but she unpins or moves the tiles so she gets confused and can not find it again. is there a way to prevent this? if there is a app that can freeze/unfreeze that would work as well.

Thanks.