Question: How much support-chanting should be practised after death of a family member?
Answer: It should be practised as continuously as possible, before the wake, during the wake and after the wake. Also, as taught by the Pure Land Tradition’s 13th Patriarch Great Master Yìnguāng (净土宗十三祖印光大师) in his ‘Fifth Reply Letter to Layperson Lǐ Jìndān’《复李觐丹居士书五》:
‘[For] 49 days [with the] sound [of the] Buddha’s [name] not interrupted, not only for [the] deceased person [does this] has benefits, for present family members, [there] are great benefits [too].‘「四十九日佛声不断，不但于亡人有益，于现在眷属大有利益。」
There should be shifts taken to practise at least  offering words of guidance (开示), followed by  mindfulness of Buddha’s name (念佛), and  dedication of merits (回向). If not yet born, this can facilitate reach of Pure Land with a higher grade of birth. If already born elsewhere, this can alleviate suffering and expedite a better rebirth.
Such practice also benefits the present family members as they create merits for personal blessings in the process. Out of seven parts of the merits created, six parts will naturally be retained by them, with one part able to be dedicated. Ideally, with right understanding, they would be nurturing the Three Provisions too.
If not possible to have constant practice personally, at least schedule daily practice along this line: purelanders.com/wake (Chanting of the Amitābha Sūtra《阿弥陀经》can be included on the seven seventh days.) During all other times, at least a Buddha name recitation device (念佛机) should be kept on at the home of the deceased. However, recorded chanting cannot offer guidance or create merits; only being a reminder to practise.
While other practices such as life liberation (放生), printing of Dharma books (印经), offering to the Triple Gem (供养三宝) and charitable donations (布施) can create merits, it is the key practice of offering guidance with mindfulness of Buddha that directs similar practice to reach Pure Land.