My apologies, there is actually another kitten I have been discussing with someone in a similar state to this poor lad that has mange and fleas. It seems a terrible day for little kittens.
Anyway, with this little lad, his GI signs are a real worry here. The bloody streaks may be due to a hemorrhagic diarrhea agent but if this has been going on a while, then it could be a side effect (secondary colitis or irritation of the gut from all the diarrhea he may have been passing). As well, the weight loss will be partly due to all his losses via stool as well as that lack of appetite.
Now further to the pushing food to get nutrition into him, we do need to tackle this for him as quickly as possible. This is because that wasting away appearance he has tells us that this has been going on too long already and is taking a toll on his body.
Therefore, it'd be ideal to have him seen urgently. Your local vet can examine him and test a stool sample to diagnose the root cause (bacterial, viral, protozoal, parasitic) so that we can start effective treatment to clear this. As well, they can give him some fluids under his skin to help get him hydrated, since diarrhea often will cause dehydration in these wee ones.
If there is any delay in having him seen, it'd be worth keeping up on the foods we discussed already and worming him with Panacur. This is a wormer but also works against worms (very common in young cats) and some of our protozoal concerns. That way we are at least ruling out some agents that could be playing a role here. Finally, if the stool is very runny, then you may want to try a cat safe anti-diarrheal treatment. They won't address infectious agents but can slow his losses from this. Ones with kaolin and probiotics (ie Propectalin, Fast Balance, Protexin Prokolin) tend to be good options in these cases.
Overall, this little one sounds to be in a precarious position here. He sounds to have had diarrhea that has been left long enough to drain the body of its resources. It will be what is causing his weakness, his likely inability to keep himself warm (which is why he needs to snuggle up and needs warmth supplementation), his wasted appearance. Therefore, we need to get him eating, wormed, and it'd be best to have him checked so that we can get treatment to settle this for him on board as quickly as possible.
Please take care,