Aqaaid

Saying words to overcome sadness and learning positive things from a person who practices shirk

Q:

1. I learnt a technique to help with sadness, this is how the technique works, you say a positive word very slowly, with intention this word will have a positive effect, is this permissible or its kufr?

2. Someone who practices shirk and kufr philosophy, would it be permissible to learn from him positive things that doesn’t have shirk and kufr? 

Attending a birthday party

Q: My wife informs me of an invite to a surprise birthday party - her sister is turning sixty tomorrow.

Would it be correct to attend, or allow family to? The sister is visited at least every fortnight, and the intention of paying a family visit could be used: what is the Shari stance?