Patients who have Obstructive Sleep Apnea (OSA) and they are hypertensive, will the treatment of OSA with CPAP help to solve their hypertension?

Yes can help certainly by good titration 

It may help patients who are hypertensive.

During asleep, patient may have their Blood pressure increased associated with sleep apnea, due to the compensation of our bodies need of oxygenated blood.

Remember when patient is on apneic events oxygen saturations decreases, and compenstaions happens by increasing blood pressure for the circulation of oxygen on our body

In people who have obstructive sleep apnea, the muscles in their throat close in and block the airway while they are sleeping. This results in heavy snoring interrupted by long silent periods when their breathing stops, followed by loud snorts and gasps as they attempt to breathe again.These gaps in breathing cause blood pressure to go up, because the oxygen level in the body falls and the brain sends signals to the blood vessels to tighten up so that oxygen flow to the heart and brain is increased. Continuous positive airway pressure (CPAP) is the most commonly prescribed treatment for obstructive sleep apnea, It pumps air into the patient's airway, which helps prevent the airway from closing.

OSA contributes to drug resistant hypertension i.e. drugs normally used to treat hypertension can not achieve satisfactory blood pressure control . Treating such patients with CPAP after titration study helps to control their hypertension .

There's no question that sleep apnea contributes to hypertension. However, effectively treating sleep apnea alone may not lower blood pressure to acceptable levels.

In men, severe obstructive sleep apnoea-hypopnoea significantly increases the risk of fatal and non-fatal cardiovascular events. CPAP treatment reduces this risk.

Studies show that in people who have moderate to severe sleep apnea  nasal continuous positive airway pressure (NCPAP) lowers blood pressure during both the day and the night.