I've made 'prayer' shawls just because the pattern was lovely, or I had the yarn to do one with. No harm, if you're giving it away,the recepient doesn't have to be in need or have a crisis in their life.
When I do make them for someone who can use some emotional support, I also support them through prayer. Others meditate, or just use the shawl as an expression of love and concern.
I'm sure your MIL will enjoy what you make for her no matter what the reason. For me, anything made with love is a treasure.
I LOVE THIS SITE!
"All good things and every perfect gift is from above, coming down from the Father of Lights who cannot change."