Moms from Cologne, Germany?

My best friend had a baby 2 months ago. She lives in Cologne and has no family or friends. She's starting to show signs of post partum depression. Unfortunately I'm in the US and I won't be able to travel until August.

What activities do you recommend for her to do there?

Any good nail salon? Spa? I'll send her a gift card for her to do something.

I sent her sushi and flowers, but I want her to get out of the house.

Thank you!