Yuzuki-san Chi no Yonkyôdai.

I've enjoyed watching this series over my morning cup of coffee. The fours brothers are so heartwarming. Gakuto and Minato, the two youngest, are so adorable. The four brothers take turns talking about their day-to-day, and the anime is character-driven rather than plot-driven. The four brothers care about each other deeply, and that's the focus of the series. The supporting characters are also fairly fleshed out, and their addition to select episodes/stories are not forced nor intrusive looking into the lives of the four brothers.

TLDR, an easy heartwarming slice-of-life anime to watch when you just want to relax.