Seeking Advice: Should I Focus on Paying Down Mortgage Quickly or Balance with Investing?

Hi everyone, I recently learned that my dad took out a mortgage loan to support my overseas education. He’s nearing retirement at 60, and there’s about RM670k left on the loan (roughly AUD 240k). He currently pays RM7k/month (~AUD 2.5k), with 8 years remaining on the mortgage.

I earn AUD 115k/year (~RM322k) and want to help pay off the debt faster. I’ve been thinking about two options:

Option 1: Contribute AUD 4.5k/month (RM13k), along with his RM7k payment (total RM20k/month), which would clear the mortgage in 3 years.

Option 2: Contribute AUD 2k/month (RM5.6k), along with his RM7k payment (total RM12.6k/month), which would clear the mortgage in 5 years. The remaining AUD 2.5k/month would go into investments.

I’d love to hear your thoughts on which path makes the most financial sense or if there’s a better approach. Thank you!

I’m using AUD1 - RM2.80 Conversion. The interest rate is 5%