My 93 Year Old Father Has Been Taking Morphine 15

My 93 year old father has been taking morphine 15 years 2-6 caps of 30mg ER. His blood pressure has always been good, 125/70 or 80 sometimes 130/90. He has trouble with sleeping and found taking 4 Morphine within 1-2 hours apart before bed to help. He is allowed up to 6 per day. Sleeping medications have cause muscle jerking for long periods of time. He began this 1 1/2 weeks ago, went to dentist to pull a tooth and BP was 175/100, checked it 2 days later 170/106. Does Morphine contribute to his BP?