There is a serial on Ganesa in which Vishnu is his doting uncle. Which scripture says this?
The Mother Goddess is mentioned as the sister of Lord Vishnu in some scriptures.
For example, in the Lalita Sahasranama, we find the following verses:
Bhanu mandala madhyastaa Bhairavi Bhaga maalini,
Padmaasana Bhagavati Padmanaabha Sahodari/
Unmesha Nimishotpanna Vipanna Bhuvanaavalih,
Sahasra Seersha Vadanaa Sahasraakshi Sahasra paat/
Aabrahmakeeta janani Varnaashrama vidhaayani,
Nijaajnaa Rupa nigamaa Punyaapunya Phalapradaa/
Shruti seemanta Sindoori kruta paadaabja dhulikaa,
Sakalaagama Sandoha Shukti Samputa Mouktikaa/
You are in the center of Surya Mandala; Bhairavi! with a garland of Suryas seated in Padmasana posture as Bhagavati the sister of Padmanabha; Devi! As you open your eyes Bhuvanaas are sprouted and destroyed as you close the eyes; You have thousand heads, faces, eyes and feet; the Unique Mother of all Beings from Brahma down to worms; the Prime Regulator of Varashrama Vidhana; Vedas are at your behest; you provide the results of every deed of the Beings as per the content of virtue or otherwise; the particles of your Lotus feet tuns red as ‘Sinduri’ which adorns the foreheads of virtuous women;
"Sahodari" means "sister" and Padmanabha is another name for Lord Vishnu.
Similarly, the Lalita Trishati Stotram from the same Brahmanda Purana has these verses:
Hakaaraarthaa Hamsa Gatirhaatakaabharanojjwalaa
Haarahaari kuchaabhoga Haakini Halya Varjitha
Harithpathi Samaaraadhyaa Hathaathkaara Hathaasura
Harsha Pradaa Havirbhoktri Haarda Santhama Saapahaa
Halleehaalasya Santhushta Hamsa Mantrartha Rupini
Hanopaadaana Nirmuktha Harshini Hari Sodari
Haahaa Hoohoo Mukha Sthutya Hani Vriddhi Vivarjitha
Hayyangavina Hridaya Harikopaarunamshukaa/
The Letter ‘Hakaara’ signifies Wealth and Gallantry being the ninth Letter of Pancha Dashaakshari; Devi! You are a Hamsa Gamana or of a Swan’s Pace; adorned with golden ornaments; your jewellery on the chest does indeed allure Shiva; you are Hakini or the One who snaps servitudes to usher freedom literally as also of the chains of Samsara; you refrain from the evil thoughts and deeds; you are adored by the Ashta Dikpalakas viz. Indra, Agni, Yama, Nirruti, Vaayu, Varuna, Kubera and Ishaana; you killed Asuras instantly and suddenly by your bravery; acclaimed as the Source of Bliss; you relish the dance of maidens ; you have unparalleled expertise in Hamsa Mantra and the regulation of Pranayaama; you are devoid of desires but distributes happiness and contentment; the sister of Hari; Gandharvas praise you on your face as Haahaa Hoohu; you are far above the features of growth, decay or death; on witnessing the tribulations of various Beings, your heart melts like butter but on getting angry your visage turns red.
In another Stotra to Goddess Kamakshi (which is also from the Lalitopakhyana portion of the Brahmanda Purana) Lord Brahma addresses her as follows:
Brahma hailed Kamakshi as follows: Jaya Devi Jaganmaatarjaya Tripurasundari,
Jaya Shrinaatha Sahajey Jaya Shri Sarva Mangaley ||
Jaganmaata! Tripurasundari! Sister of Lakshmi Pati! Sarva Mangala Rupini! You are an Embodiment of Mercy, Shrigara Nayaki, Siddheswari, saluted by Top Yogis, Jagadamba, Unfailing donor of boons to Devotees; Praised by Himashaila
Similarly, the Durga Ashtakam (not sure which scripture it is from) mentions:
Vasudeva suthe, kali,
Vasu deva sahodhari,
Vasundhara sriye nandhe,
Sri Durga Devi namosthuthe., 2
Salutations to goddess Durga, Who is the daughter of king Vasudeva, Who is the sister to Lord Vaasudeva, And who is the lady who is earth as well as Lakshmi.
So, there are some references like these.
This question is very confusing. God was never born as Vishnu. But Devi was born as both Parvati and Yogamaya. These two are separate incarnations. Yogamaya was born as sister of Krishna. So Parvati was never born as sister of Vishnu.
The hymns sees yogamaya and Parvati as forms of Supreme Goddess and Krishna as an incarnation of Vishnu. So what they mean is true in very roundabout way. In that case, Kamala is also included as a form of Shakti and so Lakshmi will become sister of Vishnu.
Streching in this way becomes meaningless.Because, after all Its One who manifests as two at the point of starting creation.They are named Purusha and Prakriti. Males and females are created for worldly procreations . So the wordly relations become confusing when applied to the Purusha and Prakriti.
The direcr answer to the question is : No scripture says.