Visitor visa for sister - no income proofs for applicant

[varx]

Hi,
I am a British citizen and want to invite my sister(alone) to the UK for a 2 month visit.
I have all the documents from my side sorted. no problems there. But I need help in my sister's side of documents.

My sister is a house wife and brother-in-law runs a small business, they don't have any tax returns or anything to prove their income.
we are attaching the following documents from her side:
- Affidavit in lieu of their marriage certificate
- Land registration papers on her name (Affidavit for translation)
- Bank statements on her name, but there is not much balance in that
- Fixed deposits on her name worth of 200,000 INR (originals)
- A photocopy of her son's study certificate from the school. (couldn't get a fresh copy as the school is closed for holidays)
- Passport photocopies of her son and husband

I will be clearly mentioning in my support letter that I will bear all expenses and will show bank statements with good balance.
Do you think this is enough?

Thanks,
Varx