Is it permissible to sit with Christians, talk to them, listen to their problems, try to solve them, and support them?

The rulings regarding interactions with the People of the Book (Christians) vary depending on their nature:

Forbidden: Sitting with them, enjoying their company, and engaging in casual conversation, as this falls under the prohibited act of showing them allegiance. Participating in their festivals and religious occasions, or giving them gifts, as this constitutes showing them allegiance and endorsing their false beliefs.

Permissible: Interacting with them for lawful purposes, such as buying and selling, as the Prophet, peace and blessings be upon him, did. Visiting their sick with the intention of presenting Islam to them. The Prophet, peace and blessings be upon him, visited a Jewish boy and his uncle Abu Talib and invited them to Islam. Resolving their problems if they request it, provided that the solution is in accordance with Islamic Sharia; otherwise, one should turn away from them.