Yeah, this genuinely doesn't seem like it'll work out, OP.
Your boyfriend doesn't have any right to remain in the UK. He's an illegal immigrant.
The fact that he's dating you is not going to be relevant. Your relationship has no legal status - you aren't married, don't have children.
& for the love of everything, don't jump into marrying him or getting pregnant - it'll be seen as contrived & won't help.
Basically, the fact that your chap is seeing you is no more relevant now than if you'd met down the pub yesterday, to be blunt.
He has no legal right to remain in the UK.
You can always see how it goes as a long distance relationship once he heads back to Pakistan? Because, honestly, he's going to be deported.
We might argue about whether immigration policies are right or not, & he might or might not be an asset to the uk if the rules were different, but he has no right to stay based on the fact that he's dating you.
You need to plan for this honestly.