OP, you're very sparing with detail and context, but you seem to want us to make a judgement.
We can't, this is between you and your dad. Some parents don't finance their adult kids, even though they can afford to, because they don't want to encourage dependency. Some don't realise how much they are struggling. Some just don't think it's their job to.
Without more information, history, or an idea of your dad's attitude to this, we can't really comment.
If you have long term health problems it's worth looking into if you would be entitled to PIP. The citizens advice can help with this. If you are getting everything you're entitled to and still struggle then find a way to get that information across to your dad, even if you don't want to ask outright.
Being resentful because he hasn't offered won't get you anywhere and will damage your relationship with him