Does investing from mom’s demat helps to save taxes? If mom is a housewife

Yes, but we need to assume that you will control her demat account and Bank account for FD, for all foreseeable future. Then you can save a great deal in taxes. For ex, you create one bank account in her name and have its online login with you, do FD in that. You will save 30% tax there. For demat, you can again save some taxes in near future, and large taxes after 10-15 yrs when you redeem/sell the equity.

One investment account for mutual fund, a demat account for direct equity, and a Bank account linked to these two, and for doing FD. So can have all these three and start.

Please do aware, that if you have siblings, all you may get into significant financial trouble with them due to this, since any money saved in the name of parents, is legally owned by all kids once the parents is no more. Even in presence of parents, this may cause several troubles with siblings. But if you are a single child, then you should definitely give this a serious thought.

You can save taxes on ltcg since you'll have an extra 1.25l from your moms demat which you'd have had to pay if all those txns were on your acc