Is it permissible to speak with a foreign woman under the pretext of promising to marry her? Is it permissible to shun one's mother for any reason? What is the punishment for severing ties of kinship?

Speaking with foreign women is not permissible except out of necessity and according to শরীয়াহ guidelines. The desire for marriage does not justify it; he should propose to her through her guardian. His estrangement from you is a severance of kinship ties and disobedience to his mother, both of which are grave sins. It is obligatory to honor and be kind to one's parents, even if they are disbelievers. Prayer forbids indecency and evil, and his statement, "There is nothing in religion but prayer," is a fabrication against Allah. Advising him is essential, preferably by elders or virtuous individuals, along with making supplications for him, especially the mother's supplication. If he repents, then praise be to Allah; otherwise, boycotting him might benefit him. It is obligatory to obey the mother in refraining from speaking with the forbidden girl. As for her refusal of his marriage to her, the principle is that he should prioritize obeying his mother, unless he fears falling into sin with the girl, in which case marriage is permissible with his mother's appeasement. It is not permissible to abandon one's mother under any pretext.