What is the ruling of Islamic law regarding a husband who brought gifts for his family and friends upon his return from travel, but limited gifts for his wife's family to a single gift for her mother, claiming that anything beyond that is not obligatory for him?

There is no blame on a husband returning from travel for not giving gifts to his wife's family, even if he gave gifts to his own family and friends. However, it is preferable, if possible, for him to give gifts to his wife's family as a gesture of honor to her and kindness to them. This is indeed a sign of noble character and perfect companionship. These matters should not be a cause for disturbing the marital relationship or an opening for Satan. Through understanding, wisdom, and thinking well of each other, affection between spouses is strengthened.