How to preserve a smell?

I'm not sure if this is the right place for this.

My brother died a few months ago, I'm in agony. I miss him constantly and I feel like nothing is right anymore. I finally convinced my mom to let me go in his preserved room and take some stuff to keep.

I grabbed some of his things and picked up a plushie and a shirt. Both smelled like him and it really made my chest ache. I'm terrified of losing the smell, as weird as that is. I used to sleep next to him almost every night and his smell just brings so many memories.

Is there anything I can do to prevent losing his scent? I know it'll dissipate over time, but for just a few weeks even. I hope this isn't weird. I really do. I'm beside myself with grief and maybe I'm not thinking clearly but idk what else to do.