Might have found something for him.
The length of flying and layovers is probably going to make him want to throttle you (or me), but hey, beggars can't be choosers!
Code:
[B][U]Date Flight Sector Dep Arr Cls A/C Connect Remarks[/U][/B]
03JAN TG 484 PER-BKK 0910 1505 J 330 8:54
03JAN TG 674 BKK-PEK 2359 0540+1 Y 330 8:15 No J availability
04JAN CA 931 PEK-FRA 1355 1715 J 773 17:25
05JAN LH 904 FRA-LHR 1040 1125 J 322 END Almost any LH flight this day (without overstepping transit to avoid consuming stopover)
There is a similar option on PVG/FRA, which is on LH rather than CA, but I haven't verified it through with a Y connection because there is no easy J connection to PVG - either you have no choice, you need to connect via PEK (on a short Y sector) or do a silly J connection (in order to avoid violating < 24 h Chinese TWOV rules).
My original idea was getting him on CA PEK/FCO (on what looks to be old equipment, 330). Problem was getting from FCO to LHR on late 5/1. Turns out it was almost impossible, unless you want to hand over a substantially silly amount of money for a Alitalia one-way direct flight (last of the night).
Generally your options were confined to finding a "day" flight on 4/1 or 5/1, but as you (and I) have both found, this is extremely difficult.
When I first chuck this into Awardtravelr, it spat out diddly-squat. I tried a simple search just to make sure AT wasn't messing me around, but no, it was telling me I had no chance in hell.
I'd run this by your BIL
ASAP; get it held by US DM with the dummy return flights and think hard about it.