Dracena is very easy to propagate. It is virtually bullet proof. Prepare a pot - 12" - with all purpose potting soil 1" from the top of the pot. Take a deep breathe. Use a pair of sharp, bypass snips. Cut off the top of the plant 8" - 10" below the canopy. Just above, not into, a leaf node - bump on the trunk where a leaf fell off. Plant the top in your pot. Give it bright sun or put it outside. Keep the soil evenly moist but not soggy. Do not fertilize. In a couple of months the top will be rooted. The existing plant will grow new side shoots from the leaf nodes below the cut.
Do not be afraid. I have a very large Dracena on my patio. It had outgrown the 18"pot that it was in. Last spring I potted it up to a 24" pot. In the process a couple of the branches broke. I cut off the broken ends and planted the branch tops. The small, cut off, broken stem ends stayed on my work table. 3 months later leaves were sprouting. They were not in soil and received no water except for rain.
If you are brave you may take another one or two 6" cuttings from the trunk, after you take the top off, and root them as well.
You will have multiple plants to honor your Sister's memory.