When you say uniform...is it an actual uniform that the company supply? If it is then prehaps your other half could casually ask him if he has enough uniforms as he has noticed them looking a little grubby/he knows how hard it is to keep them clean etc,,,,hopefully he may take the hint?
If not I do think that the MANAGER should speak to all employees as a whole rather than asking your husband to do his dirty work. If it just your partner and this guy working togther it could potentially make things very uncomfortable between them - I think your partner should point this out and tell his manager he is not comfortable doing this!