Is returning to mix with family and friends and renewing relationships with them, for the purpose of Dawah (inviting to Islam) and within legitimate Islamic boundaries, considered an act of worship for which one is rewarded?

The believer is of good character, gentle, cheerful, gets along with people, and they get along with him. He mixes with them, greets them, and smiles at them, making that a way to invite them, advise them, and guide them. He is close to people, lives among them, shares in their joys and sorrows, and strives to benefit them. The Sunnah has indicated these noble manners, for in the Hadith: "The most complete in faith among the believers are those with the best character, who are humble and gentle, who get along with others and with whom others get along. And there is no one from us who does not get along with others and with whom others do not get along." And His (peace be upon him) saying: "Indeed, you will not be able to embrace all people with your wealth, but you can embrace them with a cheerful face and good character." And his saying: "Your smile in the face of your brother is charity for you."

Adorning oneself with good character and mixing with people to invite and advise them, while maintaining a pure intention, is sound judgment and wisdom in dealing, and is rewarded in two ways: adorning oneself with good character, and drawing closer to people to invite them.