It’s encouraging that your mom is being seen by a hematologist. Often, though knowledgeable, primary care physicians aren’t necessarily the best doctor for treating blood conditions. Since your mom just started taking a higher dosage of HU a couple of days ago, she may need to give herself more time for her body to adapt to the medication. I don’t say this lightly because I’ve had my share of medications over the past few years and the first couple of week of adjustments can be very trying. So tell her to hang in there! 😉
And encourage her to drink that water! I’ve found I’m able to really take in a lot more water if I drink it at room temperature.

Is she taking the HU with food? Other members have mentioned that it can help lessen the tummy queasiness. She might try some candied ginger candy to help with that.

I’m sure her doctor is expecting that with this higher dosage of HU, mom should see her platelet numbers decreasing in subsequent blood work. It can take some tweaking to get a good balance of meds vs return. If her numbers drop appreciably she might even be able to return to the lower dosage at some point.

How often are her blood labs done?