Investment Options for an NRI

As an Indian citizen living in Dubai, I've begun investing in two mutual funds through my NRO account at ICICI. I'm eager to expand my investments but have some questions regarding the limitations I face as an NRI. I'm planning topening a Demat account for stock investments, and I also have a regular SBI account in India. Can I use this SBI account for stock investments or for purchasing additional mutual funds via brokerage apps? Or do I need to open a Demat account linked to my NRO account? Additionally, a friend suggested that I could open a Demat account in my mother's name and manage it myself. Is this a viable option for managing my investments? Thank you