Dracaena Marginata - help

I am having problems with my dracaena marginata. When I received it 2 years ago, it had 5 "shoots" in the pot. I have had two of the shoots die. I think I am overwatering because the leaves are falling off and the stem were mushy. How do I dry out the plant? Can I separate the 3 remaining plants or would that make it worse? This was a gift from my mother's funeral and I don't want to lose them. Please help!

Sounds like over-watering to me. One thing you DON'T want to do is put it in the sun to dry out- this will sunburn the leaves (permanently). here's what I would do- I wouldn't separate the stems- But I think I would repot it- make sure the pot has large drainage holes- and use a faster draining potting soil- you can do this by adding perlite to reg. potting soil. If re-using a pot- be sure to sterilize it (and your tools) with a 10% bleach solution. Trim off any rotted stems and damaged roots. Make sure the plant is getting bright light- but not direct sunlight. Let the top inch of soil dry out before watering- since you think over watering might be the problem. Also- When you water- be sure the plant is not left in a saucer full of water. If it is a large plant and you can't easily empty water out of the saucer- use a turkey baster to suck out the extra water.
Hope this helps!

Yes, definitely repot. I would use a new, clean container in case there are diseases or fungus present. Do not jump to a much larger pot, increase the size gradually through time. Make sure the soil level remains the same in the new pot and yes, use courser soil or mix sand or perlite into a potting mix. I would buy a soil moisture meter if you are prone to over (or under) water. The top inch of soil may not tell the whole story of the plant's moisture. This plant actually likes to be on the dry side!