Can I only join a flight on the 2nd leg of the ticket at the ticketed "stopover"?

I accidently booked a flight under my husband’s “preferred” name as opposed to birth/passport name using points. Route Syd - Kuala Lumpur.
Next leg is KL - Paris via Sri Lanka. Malaysian Airlines wouldn’t do a name change and Qantas FF advised me to cancel and rebook. Problem is that seat will be allocated firstly to Qantas Gold then silver and eventually bronze (us). There are currently no reward seats left in business or any other class for that matter. I can, however, get him on Sydney - Sri lanka at the same time as the original flight and will be there for the 2nd leg of the next journey. Two separate airlines MAS and Sri Lankan. Do you think he could board that flight in Colombo even though it is ticketed to start in KL? Sorry for the confusion. Wondering what my options are as I don’t want to lose my seat as well if I don’t have to. I booked these 11 months in advance it took ages. Thanx in advance.
Shauna

Hello and welcome @shauna1,
I may be wrong, but I believe that if you are a no-show for the first leg of a booking like you have described, all remaining sectors on the trip will be cancelled.

Thank you I was afraid of that.

Hi Shauna,
I really hope you can resolve this issue with a positive outcome, somehow.