Eric,
Based on the litzen on his cuffs, he's from one of these four Garde Grenadier regiments...
Kaiser Alexander Garde-Grenadier-Regiment Nr.1
Kaiser Franz Garde-Grenadier-Regiment Nr.2
Königin Elisabeth Garde-Grenadier-Regiment Nr.3
Königin Augusta Garde-Grenadier-Regiment Nr.4
It's kind of hard to see, but it looks like the inside material on his epaulettes is very pale, so he's probably from Kaiser Alexander Garde-Grenadier-Regiment Nr.1.