Ah

I looked this up online. If you give flowers make it is an odd number.
Always wrap the gift, but simple wrap..Pastel paper, no bows..

GIFTS TO AVOID

Lilies, lotus blossoms, and camellias are associated with funerals. White flowers of any kind should be avoided. There is also a superstition that potted plants encourage sickness.

Giving four or nine of anything is considered unlucky.

Red Christmas cards should be avoided, since funeral notices are customarily printed in this colour.

All of this being said.. My husband said maybe you could take a photo of the business and have it printed today.. 5x8 (Walgreens) and then place it with a matte in a frame (8x10).
Sign it with "Best wishes on this 5th anniversary.. Date it and put the city on it. "

Maybe a nice Japanese floral arrangement, or a little bonsai tree (not sure what the cost would be)

My hubby and are on a home made gift kick. Since your friend owns a restaurant, is there something unique you could make for a cook or something?

We've been making herbal salt and giving it to people (with herbs from our garden).

Do you have any pictures of the friend at the restaurant that they don't have? A picture in a frame might be a nice gesture.

wine is always a nice jester.