Is it permissible to visit one's sister's husband in the hospital with the family?

The Sharia encourages visiting the sick, and this is one of the rights a Muslim has over his brother. There is no difference in this regard between a man and a woman. However, a woman going out has conditions, including: modesty in dress, not being in seclusion with a non-mahram man, avoiding mixing with men, not speaking in a soft or alluring tone, the community being safe for her to go out, and obtaining her husband's permission if she is married. If these conditions are met, then there is no objection to the visit.