Is it permissible to talk about good social conditions and family warmth in front of a friend who is suffering from family and financial problems, fearing that such talk might hurt her, despite her positive interaction?

Speaking of blessings is required as a form of gratitude to Allah, unless it is done out of forbidden pride and arrogance, or if there is a fear of an envious person's envy, or a fear of hurting the feelings of one who is deprived. So, if harm is feared from speaking of a blessing, it is better to conceal it.