Sam, it's really hard isn't it - lots of us sympathise.
When I had ds2, ds1 was exactly 2 and like you, I struggled to get a routine established, but got there in the end!
DH generally isn't around for bedtime (wish he was around from 7.00 but ho hum!)
As others have said I would give ds1 his teatime meal just after ds2 had fed (did this at 5.30pm, anticipating him crying for food at 6.00).
I too had a Graco swing (borrowed from sil) and put baby in there (in kitchen, next to table).
After ds1 teatime, we'd all troop upstairs and I would bath each of them on ALTERNATE nights. This way ds1 either had a nice bath to himself or helped me bath the baby which he loved, and on both nights was getting plenty of attention. When ds1 was having his bath, ds2 would be in one of those lie back baby seat things that have toys hanging from them. Like the swing, he was safe in there and could see us. The seat was very portable, so if I hadn't had a swing, I would have used this in the kitchen at teatime too.
After bath, we'd then go in to ds1's room. By this time it was coming up to 7.00pm. Would put ds2 on floor on some blanket with some toys around to gaze at. Get both ready for bed. Read ds1 story. Tuck him in bed. Put ds2 in his cot in our room, put musical mobile on. Hope he would sleep until next feed which was about 9ish from recollection.
It will get easier as you get your routine going and when (hopefully) the baby starts to sleep through you begin to feel vaguely human again.
Good luck.