Right:
-
Don't use woolite - it isn't actually meant for wool any more!
-
Felting is caused by extreme changes of temperature and agitation (rubbing), so you are not going to felt this precious thing by soaking it.
So, if it were mine, I would get a washing up bowl of hand-hot water - about the temp you'd be able to was dishes in without gloves - and add about a teaspoonful of dishwashing detergent.
Mix thoroughly, then add your precious blanket and gently squish it under the water. Leave for half an hour or so, and move it gently around - no rubbing! - to make sure that any dirt etc has a chance to float out.
Lift the blanket out of the water, keeping it supported from underneath so it doesn't stretch out, and put it in a colander or similar to drain.
Rinse out the washing up bowl, and fill it with clean water at the same temperature as the (now slightly cooler) water you've drained away.
Put the blanket in the clean water and swish it around gently to remove the soap.
Repeat the drain and rinse at least twice more.
Finally, put the blanket inside some dry clean towels and squeeze to remove most of the water. Spread it out to dry on another clean dry towel (don't hang it as it may stretch oddly) and hopefully that will work.
You can actually boil a wool garment without ruining it - that's how things are dyed!