I have a good friend who have family/married now. Is it permissible to stay over his house for 1 or 2 days? What is the best conduct according to Hadist when visiting muslim house?
This is permissible providing his wife and daughters abide by the proper hijab, do not free mix, and have enough space in their house so that their hijab is not jeopardized. You must also lower your gaze and not mix with them whatsoever. The Sunnah is to make dua for your host who fed you and you can find such duas in a booklet called ‘Fortress of the Muslim’.