Hello Scarlett and welcome to the forum. I’m so sorry to hear about your dad and sorry too that you’ve had to postpone university. How is your dad’s mobility?
For the first 6 months for the brain, it’s all about healing and recovering. And to do that it’s tiring so he will be resting a lot. The brain is very much in charge, and fatigue is way of controlling how much he does. That’s how I always saw it anyway 
He’s just experienced a life threatening event so naturally he is in shock. Emotions can be very much heightened plus his body is adjusting to the medication. It’s all a bit of a rollercoaster ride emotionally but it should gradually settle down over the coming months.
Is he receiving any kind of speech therapy for is Aphasia.
Also, there may be a local Aphasia group or stroke group in your area he might be able to attend.
They would be an excellent place for confidence building and tips/advice from fellow survivors and their carers.
I attend a local Aphasia group once a month run by the SA, its a self help group. As well as talks and activities, there are regular trips out too and it all helps with building confidence, helps restore a sense of independence and purpose in life, and plenty of practice with speaking to others without feeling a fool.
If you haven’t already, you might find your local Stroke Association’s Aphasia/Stroke groups from the link below:
Support groups in your area | Stroke Association
But don’t limit yourself, there maybe Aphasia groups run by other organisations, just google Aphasia groups for your local area to see what might be available.
Do make good use of the SA Helpline @Mabel1 mentioned above. You are not alone here, there will be many others coming along soon so keep coming back here. And do make good use of the search bar above, just click on the magnifying glass 
above right. There are many carers as well as stroke survivors on here so there are plenty of posts with some good advice. Also check out the welcome post some of us put together on what we wish we’d been told at the start. And here’s some more 40 things
As @Mabel1 said, so long as you are meeting his basic needs, clean, fed, medications and helping with physio, there’s not a lot else you can do. And its hard to advise with knowing his physical abilities are and what he’s capable of.
You will have to take your cues from your dad as to how/when to keep him entertained/occupied, physio alone can wipe out for an hour afterwards, likewise any speech therapy, tv might be too much noise. He may have the attention span of a Gnatt, same goes for short term memory, they too will gradually improve over time. In the meantime though, it means that anything he turns to that interest him or even his physio will all be in very short bursts. 15mins here, half an hour there, it all depends on how taxing it has been on his brain. But give him plenty of encouragement and reassurance that it can and will get better in time. His speech will improve, 6mths from now he’ll be better than he is today, a year from now he’ll be even better again.
Just don’t let him lose faith or hope that it will get better. This is a marathon not a race. And you’re not alone 
Lorraine
Stroke Improvement Group